April 2019 - Challenge

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This month's challenge is from Reda Kebbaj. (Thanks!)

Find nine different prime numbers that can be placed in a 3x3 square in such a way that the average of every row, column, and diagonal is also a prime number.




We will post the names of those who submit a correct, original solution! If you don't want your name posted then please include such a statement in your submission!

We invite visitors to our website to submit an elegant solution. Send your submission to the ponder@il.ibm.com.

If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com

Challenge: 27/03/2019 @ 12:00 PM EST
Solution: 03/05/2019 @ 12:00 PM EST
List Updated: 06/05/2019 @ 12:00 PM EST

People who answered correctly:

Adam Daire (27/03/2019 04:23 PM IDT)
Daniel Chong Jyh Tar (27/03/2019 04:47 PM IDT)
Amos Guler (27/03/2019 05:53 PM IDT)
Sanandan Swaminathan (27/03/2019 06:29 PM IDT)
Kevin Bauer (27/03/2019 06:38 PM IDT)
JJ Rabeyrin (27/03/2019 10:35 PM IDT)
Lorenz Reichel (27/03/2019 11:32 PM IDT)
Alper Halbutogullari (27/03/2019 11:43 PM IDT)
Bert Dobbelaere (27/03/2019 11:46 PM IDT)
Eden Saig (28/03/2019 01:14 AM IDT)
Bryce Fore (28/03/2019 01:26 AM IDT)
Anders Kaseorg (28/03/2019 05:20 AM IDT)
Graham Hemsley (28/03/2019 11:47 AM IDT)
Joaquim Neves Carrapa (28/03/2019 11:54 AM IDT)
Uoti Urpala (28/03/2019 12:06 PM IDT)
Xiao Liu (28/03/2019 02:14 PM IDT)
Robert Lang (28/03/2019 04:10 PM IDT)
Alex Fleischer (28/03/2019 06:01 PM IDT)
Evert van Dijken (28/03/2019 07:04 PM IDT)
Oscar Volpatti (28/03/2019 08:16 PM IDT)
Deniz Yuret (28/03/2019 09:44 PM IDT)
Todd Will (28/03/2019 11:29 PM IDT)
Hugo Pfoertner (28/03/2019 11:40 PM IDT)
Chuck Carroll (28/03/2019 11:44 PM IDT)
Evert van Dijken (29/03/2019 12:32 AM IDT)
Haye Chan (29/03/2019 03:05 AM IDT)
Gary M. Gerken (29/03/2019 04:45 AM IDT)
Dan Dima (29/03/2019 10:47 AM IDT)
Armin Krauß (29/03/2019 12:55 PM IDT)
Harald Bögeholz (29/03/2019 03:42 PM IDT)
Sergey Coolcat (29/03/2019 03:08 PM IDT)
Matthew Charlap (29/03/2019 04:53 PM IDT)
Guillaume Escamocher (29/03/2019 06:49 PM IDT)
Alexander Daryin (29/03/2019 08:09 PM IDT)
Kai Guttmann (29/03/2019 09:47 PM IDT)
Rashid Naimi (30/03/2019 01:48 AM IDT)
Marco Bellocchi (30/03/2019 02:06 AM IDT)
Mehmet Saruhan (30/03/2019 02:37 AM IDT)
Pål Hermunn Johansen (30/03/2019 03:20 AM IDT)
Andreas Stiller (30/03/2019 05:29 AM IDT)
Xiao Liu (30/03/2019 07:34 AM IDT)
Clive Tong (30/03/2019 10:18 AM IDT)
Richard Gosiorovsky (30/03/2019 12:22 PM IDT)
Sanandan Swaminathan (30/03/2019 12:40 PM IDT)
Philippe Fondanaiche (30/03/2019 01:03 PM IDT)
Noam & Ayal Zaks (30/03/2019 01:54 PM IDT)
Michael Liepelt (30/03/2019 02:35 PM IDT)
Thomas Huet (30/03/2019 05:19 PM IDT)
Paul Revenant (30/03/2019 09:36 PM IDT)
Florian Fischer (30/03/2019 11:24 PM IDT)
Boaz Menuhin (31/03/2019 01:08 AM IDT)
Raymond Lo (31/03/2019 09:01 AM IDT)
Kang Jin Cho (31/03/2019 12:01 PM IDT)
Thomas Egense (31/03/2019 12:58 PM IDT)
Anson Ho (31/03/2019 01:05 PM IDT)
Vladimir M. Milovanović (01/04/2019 02:12 AM IDT)
Prashant Wankhede (01/04/2019 03:49 AM IDT)
Frank Schoeps (01/04/2019 05:16 AM IDT)
Tom Chen (01/04/2019 06:12 AM IDT)
David F.H. Dunkley (31/03/2019 07:08 PM IDT)
Walter Schmidt (01/04/2019 08:25 AM IDT)
Shouky Dan & Tamir Ganor (01/04/2019 11:23 AM IDT)
Rudy Cortembert (01/04/2019 11:46 AM IDT)
Brett Grothouse (01/04/2019 11:54 AM IDT)
Reiner Martin (01/04/2019 12:42 PM IDT)
Christian Pfaffenzeller (01/04/2019 04:41 PM IDT)
Charles Joscelyne (01/04/2019 04:51 PM IDT)
Vanio Beccaccioli (02/04/2019 12:10 AM IDT)
Rick Kaye (02/04/2019 02:46 AM IDT)
Alan Murray (02/04/2019 03:52 AM IDT)
Gumpina Rama Krishna Chaitanya (02/04/2019 06:08 AM IDT)
Johnathon Shook (02/04/2019 08:01 AM IDT)
Alex Fleischer (02/04/2019 08:59 AM IDT)
Anunay Kulshrestha (02/04/2019 09:03 AM IDT)
Dieter Beckerle (02/04/2019 10:07 AM IDT)
K.S.G. Sarma (02/04/2019 03:38 AM IDT)
Frank Schoeps (02/04/2019 03:47 PM IDT)
Yash Patil (02/04/2019 06:36 PM IDT)
Cameron Byer (02/04/2019 06:52 PM IDT)
Yash Pote (02/04/2019 10:54 PM IDT)
Muharrem Gorkem (03/04/2019 12:12 AM IDT)
Caili Shen (03/04/2019 12:32 AM IDT)
Jordan Rinder (03/04/2019 01:49 AM IDT)
You Soon Ho (03/04/2019 10:27 AM IDT)
Nguyen Khac Tung (03/04/2019 01:16 PM IDT)
Kandala Viswakanth (03/04/2019 03:39 PM IDT)
Benjamin Buhrow (03/04/2019 04:42 PM IDT)
Franciraldo Cavalcante (03/04/2019 05:07 PM IDT)
Rogerio Ponce da Silva (03/04/2019 06:00 PM IDT)
Luke Richards (03/04/2019 06:09 PM IDT)
Latchezar Christov (03/04/2019 08:14 PM IDT)
Kandala Srinivas (03/04/2019 08:26 PM IDT)
Wayne Petrychyn (03/04/2019 08:38 PM IDT)
Deron Stewart (03/04/2019 10:55 PM IDT)
Phil Benamy (04/04/2019 02:48 AM IDT)
Hannah Leaman (04/04/2019 03:21 AM IDT)
Yuanjie Pu (04/04/2019 07:11 AM IDT)
Hayk Aleksanyan (04/04/2019 09:39 AM IDT)
Rustam Salikhov (04/04/2019 10:12 AM IDT)
Aditya Dalal (04/04/2019 01:56 PM IDT)
Vladimir Volevich (04/04/2019 03:05 PM IDT)
Dominik Reichl (04/04/2019 05:32 PM IDT)
Peter Gerritson (04/04/2019 09:13 PM IDT)
Paul McKenney (04/04/2019 0921:46 PM IDT)
Michael Rosola (04/04/2019 11:48 PM IDT)
Rainer Rosenthal (05/04/2019 01:16 AM IDT)
Spencer Ong (05/04/2019 12:58 PM IDT)
Daniel Bitin (05/04/2019 01:38 PM IDT)
Mantha Bharadwaj (05/04/2019 01:52 PM IDT)
Seth Cohen (05/04/2019 02:44 PM IDT)
Kipp Johnson (05/04/2019 04:35 PM IDT)
Yuxuan Shui (05/04/2019 05:53 PM IDT)
Kandala Srinivas (05/04/2019 07:37 PM IDT)
Kkm Sarma (05/04/2019 10:41 PM IDT)
Soumitra Agarwal (06/04/2019 06:08 AM IDT)
David Friedman (07/04/2019 07:40 AM IDT)
Mauro Bampo (07/04/2019 03:28 PM IDT)
Min Jung Kim (07/04/2019 04:36 PM IDT)
Jeewoo Lee (07/04/2019 05:24 PM IDT)
Fabio Michele Negroni (07/04/2019 05:47 PM IDT)
Marcelo De Barros (08/04/2019 01:41 AM IDT)
Jonas Beachy (08/04/2019 01:56 AM IDT)
Francisco Couzo (08/04/2019 03:06 AM IDT)
Serge Batalov (08/04/2019 03:56 AM IDT)
Bharat Kumar Aryasomayajula (07:12 AM IDT)
Ulf Brännlund (08/04/2019 09:21 AM IDT)
Kenneth Kwok (08/04/2019 10:37 AM IDT)
Rajesh Sathiyanarayanan (08/04/2019 11:21 AM IDT)
Vivek Nema (08/04/2019 05:14 PM IDT)
Maximilian Maczasek (08/04/2019 09:13 PM IDT)
Yasodhar Patnaik (08/04/2019 10:58 PM IDT)
Greg Janée (09/04/2019 07:15 PM IDT)
David Keyes (10/04/2019 01:49 AM IDT)
Fabio Filatrella (11/04/2019 11:41 AM IDT)
Harold Gutch (11/04/2019 11:45 AM IDT)
Sebastian Bohm & Martí Bosch (11/04/2019 01:08 PM IDT)
Dario Filatrella (11/04/2019 06:30 PM IDT)
Hanlin Ren (12/04/2019 08:10 AM IDT)
Andrejs Pilka (12/04/2019 01:40 PM IDT)
Nigel Brumpton (12/04/2019 06:51 PM IDT)
Barry O’Sullivan (13/04/2019 01:48 AM IDT)
Ryan Riley (13/04/2019 09:53 AM IDT)
David Greer (13/04/2019 10:46 PM IDT)
Fakih Karademir (14/04/2019 12:15 PM IDT)
Boris Silantyev (14/04/2019 01:57 PM IDT)
Eoin Kenny (14/04/2019 02:54 PM IDT)
Yi Won Kim (14/04/2019 05:10 PM IDT)
Almog Yair (14/04/2019 10:44 PM IDT)
Joseph DeVincentis (15/04/2019 17:28 PM IDT)
Andreas Knüpfer (15/04/2019 10:28 PM IDT)
Maksym Voznyy (16/04/2019 05:51 AM IDT)
Low Choo Ray (16/04/2019 08:52 AM IDT)
Misha Lavrov (16/04/2019 11:21 PM IDT)
Jingran Lin (17/04/2019 01:17 AM IDT)
Tom Sirgedas (17/04/2019 01:48 AM IDT)
Ignat Soroko (17/04/2019 11:12 AM IDT)
Hamidreza Bidar (18/04/2019 03:04 PM IDT)
Mikhail Berezovskiy (20/04/2019 07:22 AM IDT)
Cheng Xizhe (20/04/2019 03:04 PM IDT)
Hakan Summakoğlu (20/04/2019 06:11 PM IDT)
Joonsoo Lee (20/04/2019 07:20 PM IDT)
Shail Patel (21/04/2019 02:20 AM IDT)
Andrew Lee (21/04/2019 04:33 PM IDT)
Jiho Lee (21/04/2019 05:22 PM IDT)
Hashimoto Ryuichi (22/04/2019 08:08 AM IDT)
Motty Porat (22/04/2019 09:57 PM IDT)
Vladimir Dorofeev (23/04/2019 02:58 PM IDT)
Erik Hostens (23/04/2019 04:42 PM IDT)
Philip Grabowski (23/04/2019 10:23 PM IDT)
Hannes Schenck (23/04/2019 11:15 PM IDT)
Hao Zheng (24/04/2019 12:05 AM IDT)
Walter Sebastian Gisler (24/04/2019 12:17 PM IDT)
Erik Wünstel (24/04/2019 12:49 PM IDT)
Ismail Bozkurt (25/04/2019 01:46 AM IDT)
Muhammed Halbutogullari (25/04/2019 06:27 AM IDT)
Steven Langerwerf (25/04/2019 06:00 PM IDT)
Alexey Zyl (26/04/2019 03:22 PM IDT)
Eric Edward Pauley (26/04/2019 07:55 PM IDT)
Jason Ke (27/04/2019 01:49 AM IDT)
Arnab Moitra (27/04/2019 12:39 PM IDT)
Feyzullah Egriboyun (27/04/2019 02:08 PM IDT)
Kelvin Kim (27/04/2019 06:27 PM IDT)
Samhita Madduri (28/04/2019 05:34 AM IDT)
Andrea Andenna (28/04/2019 12:30 PM IDT)
Andras Varga (29/04/2019 12:24 PM IDT)
Tilo Anschütz (29/04/2019 01:42 PM IDT)
Ralf Jonas (29/04/2019 04:29 PM IDT)
Jun Sakai (29/04/2019 05:34 PM IDT)
Michael J. Swart (29/04/2019 11:58 PM IDT)
Elizabeth Harper (30/04/2019 12:04 AM IDT)
Stefan Wirth (30/04/2019 02:04 AM IDT)
Daniëlle van den Berg (30/04/2019 04:30 PM IDT)
Radu-Alexandru Todor (30/04/2019 09:08 PM IDT)