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 A306717 #7 Mar 08 2019 20:12:16 %S A306717 1,1,1,2,1,2,1,2,2,1,1,1,3,1,1,2,1,2,2,1,2,2,2,2,1,2,2,2,4,2,3,1,1,3, %T A306717 2,4,4,4,5,2,1,2,5,4,4,1,4,5,4,2,2,4,5,4,1,1,1,7,2,4,3,4,2,7,1,1,2,1, %U A306717 2,5,4,5,5,4,5,2,1,2,1,2,5,1,5,5,4,5,5 %N A306717 Square array T(n, k) of positive integers, n > 0, k > 0, read by antidiagonals, filled the greedy way, such that for any i >= 0 and j >= 0 with i + j > 0, no three terms T(n, k), T(n+i, k+j), T(n+2*i, k+2*j) form an arithmetic progression. %C A306717 This sequence is a 2-dimensional variant of A229037. %H A306717 Rémy Sigrist, <a href="/A306717/a306717.png">Colored representation of T(n, k) for n = 1..1000 and k = 1..1000</a> (where the hue is function of T(n, k)) %H A306717 Rémy Sigrist, <a href="/A306717/a306717.txt">C++ program for A306717</a> %F A306717 T(n, k) = T(k, n). %F A306717 T(n, 1) = T(n, 2) = A229037(n). %o A306717 (C++) See Links section. %Y A306717 Cf. A229037. %K A306717 nonn,tabl %O A306717 1,4 %A A306717 _Rémy Sigrist_, Mar 06 2019