This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A082002 #10 Dec 05 2013 19:56:03 %S A082002 1,2,3,6,12,4,8,18,10,9,15,24,14,30,16,20,36,22,42,40,21,27,28,48,54, %T A082002 26,45,32,34,60,50,66,70,56,72,33,39,44,78,84,80,75,38,51,46,52,69,68, %U A082002 90,96,98,102,88,104,57,63,76,108,110,114,105,100,120,92,117,58,62,87,126 %N A082002 Square array read by antidiagonals, alternating upwards and downwards: T(1, 1) = 1 and every other entry is the smallest number not already used that has a common factor with every number in its row and column, not including the 1. %C A082002 This is the boustrophedon method of filling an array. %e A082002 1, 2, 4, 8, 14, 16, ... %e A082002 3, 12, 18, 24, ... %e A082002 6, 10, 20, ... %e A082002 9, 30, ... %e A082002 15 ... %Y A082002 Cf. A082003, A082004, A082005. %K A082002 nonn,tabl %O A082002 1,2 %A A082002 _Amarnath Murthy_, Apr 05 2003 %E A082002 More terms from _David Wasserman_, Jul 30 2004