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 A082017 #6 Dec 05 2013 19:56:04 %S A082017 1,2,7,6,18,15,28,29,49,45,75,66,94,91,130,120,155,153,201,190,232, %T A082017 231,288,276,325,326,391,378,462,435,508,496,589,561,641,630,732,703, %U A082017 790,780,891,861,955,946,1066,1035,1136,1128,1257,1225,1333,1326,1464,1431 %N A082017 First row of square array T(n,k) with T(1,1) = 1 where antidiagonals are filled alternating upwards and downwards with the smallest number not already used such that the n-th antidiagonal sum is a multiple of n. %e A082017 T(n,k) begins: %e A082017 1, 2, 7, 6, 18, 15, ... %e A082017 4, 5, 8, 14, 16, 27, ... %e A082017 3, 9, 12, 17, 26, 31, ... %e A082017 13, 11, 19, 25, 32, 42, ... %e A082017 10, 20, 24, 33, 41, 50, ... %e A082017 21, 23, 34, 39, 51, 60, ... %Y A082017 Cf. A074135, A082018, A082019, A082020, A082002, A082003, A082004, A082005. %K A082017 nonn %O A082017 1,2 %A A082017 _Amarnath Murthy_, Apr 05 2003 %E A082017 Edited and more terms from _Alois P. Heinz_, Oct 26 2011