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 A082018 #8 Dec 05 2013 19:56:04 %S A082018 1,4,3,13,10,21,22,40,36,64,55,81,78,115,105,138,136,182,171,211,210, %T A082018 265,253,300,301,364,351,433,406,477,465,556,528,606,595,695,666,751, %U A082018 741,850,820,912,903,1021,990,1089,1081,1208,1176,1282,1275,1411,1378 %N A082018 First column 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. %C A082018 This is the boustrophedon method of filling an array. Sums of antidiagonals of T are in A074132. Sums of antidiagonals of T divided by number of antidiagonals are in A074133. Diagonal of T is in A082019. %e A082018 T(n,k) begins: %e A082018 1, 2, 7, 6, 18, 15, ... %e A082018 4, 5, 8, 14, 16, 27, ... %e A082018 3, 9, 12, 17, 26, 31, ... %e A082018 13, 11, 19, 25, 32, 42, ... %e A082018 10, 20, 24, 33, 41, 50, ... %e A082018 21, 23, 34, 39, 51, 60, ... %Y A082018 Cf. A074135, A082017, A082019, A082020, A082002, A082003, A082004, A082005. %K A082018 nonn %O A082018 1,2 %A A082018 _Amarnath Murthy_, Apr 05 2003 %E A082018 Edited and more terms from _Alois P. Heinz_, Oct 26 2011