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 A189218 #4 Mar 30 2012 17:22:58 %S A189218 2,6,2,12,81,2,2,25,143,2,5,6,42,221,2,3,9,8,63,315,2,10,2,14,10,88, %T A189218 425,2,2,0,56,20,12,117,551,2,0,7,13,0,27,14,150,693,2,5,4,2,11,61,35, %U A189218 16,187,851,2,3,3,4,28,11,43,44,18,228,1025,2,15,9,0,99,1989,609,117,54,20,273,1215,2 %N A189218 Triangle read by rows of the index of the least n-gonal number A189216(n,k). %C A189218 The n-th term of the n-th row is 2. The first and second columns are A188894 and A188898. %e A189218 The triangle begins: %e A189218 2 %e A189218 6, 2 %e A189218 12, 81, 2 %e A189218 2, 25, 143, 2 %e A189218 5, 6, 42, 221, 2 %e A189218 3, 9, 8, 63, 315, 2 %e A189218 10, 2, 14, 10, 88, 425, 2 %e A189218 2, 0, 56, 20, 12, 117, 551, 2 %e A189218 0, 7, 13, 0, 27, 14, 150, 693, 2 %K A189218 nonn,tabl %O A189218 3,1 %A A189218 _T. D. Noe_, Apr 18 2011