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 A332986 #10 Mar 09 2020 21:01:17 %S A332986 1,4,6,18,2,7,1,4,1,2,4,5,5,3,1,2,2,5,3,3,4,3,1,10,1,1,8,3,4,7,5,12, %T A332986 10,8,9,7,3,5,3,6,3,10,11,1,2,13,9,6,3,2,1,2,3,3,2,2,6,13,9,4,1,11,1, %U A332986 3,8,9,1,4,6,3,8,3,5,2,3,2,5,1,14,9 %N A332986 Successive differences of index of triangular numbers sum of two pentagonal numbers. %C A332986 The behavior of this sequence is unexpectedly quite complex. %H A332986 Peter Kagey, <a href="/A332986/b332986.txt">Table of n, a(n) for n = 1..2500</a> %Y A332986 Cf. A000217 (triangular numbers), A000326 (pentagonal numbers), A332987 (sums of two nonzero pentagonal numbers), A333009 (analog for indices of square numbers). %Y A332986 Cf. First differences of A332985. %K A332986 nonn %O A332986 1,2 %A A332986 _Olivier Gérard_, Mar 05 2020