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 A013322 #16 Apr 05 2015 11:02:35
%S A013322 1,3,3,3,6,6,6,10,10,10,15,15,15,15,15,15,21,21,21,21,21,21,28,28,28,
%T A013322 28,28,28,36,36,36,36,36,36,36,36,36,36,45,45,45,45,45,45,45,45,45,45,
%U A013322 55,55,55,55,55,55,55,55,55,55,66,66,66,66,66,66,66,66,66,66,66,66
%N A013322 Golomb-type sequence over triangular numbers.
%C A013322 All terms are triangular numbers; a(n) is length of n-th run.
%C A013322 It is understood that a(n) is taken to be the smallest number >= a(n-1) which is compatible with the description.
%C A013322 The apparent idempotence, a(a(n))=a(n), holds while n<191 and breaks after that. - _Ivan Neretin_, Apr 03 2015
%H A013322 Ivan Neretin, <a href="/A013322/b013322.txt">Table of n, a(n) for n = 1..10000</a>
%p A013322 A:= 1,3,3,3:
%p A013322 for n from 4 to 30 do
%p A013322 t:= n*(n-1)/2;
%p A013322 A:= A, t$A[n-1]
%p A013322 od:
%p A013322 A; # _Robert Israel_, Apr 03 2015
%t A013322 a = {1, 3, 3, 3}; Do[a = Join[a, Array[i(i+1)/2&, a[[i]]]], {i, 3, 11}]; a (* _Ivan Neretin_, Apr 03 2015 *)
%Y A013322 Cf. A001462.
%K A013322 nonn,easy
%O A013322 1,2
%A A013322 _N. J. A. Sloane_