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 A096662 #4 Mar 30 2012 17:38:57
%S A096662 3,6,21,231,26796,359026206,64449908476890321,
%T A096662 2076895351339769460477611370186681,
%U A096662 2156747150208372213435450937462082366919951682912789656986079991221
%N A096662 Least nontrivial n-tuply triangular number.
%F A096662 a(n)=A007501(n). [From _R. J. Mathar_, Sep 04 2008]
%t A096662 f[n_] := n(n + 1)/2; Table[ Nest[f, 2, n], {n, 10}]
%Y A096662 Cf. A000217, A002817, A064322, A066370.
%K A096662 nonn
%O A096662 1,1
%A A096662 _Robert G. Wilson v_, Jul 02 2004