In this 5x5 grid I have inserted a sequence of 24 3-digit numbers according to some algorithm. The next number goes into the center square; what is this 3-digit number? And what can you say about the algorith I used?

141 406 974 169 653

820 197 592 383 944

816 643 ??? 589 399

884 105 238 592 279

462 307 502 375 793

Hint: I found this puzzle idea one night last March while going through an old chest of drawers. I first tried to make the problem as a 4x4 grid, but I found I could not do it. I could have made larger grids (the sequence does not stop after the 25th number), but settled on 25 as a nice, round number.

286. The numbers are the first 75 digits of pi after the decimal point. Pi=3.141592653589793238462643383279502884197169399375105820974944592307816406286...

Posted by Math Man on 2020-04-06 13:16:36