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 A279951 #9 May 08 2017 00:28:35 %S A279951 1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4, %T A279951 4,4,6,6,6,6,6,6,6,6,6,8,8,8,8,8,8,8,8,8,10,10,10,10,10,10,10,10,10, %U A279951 12,12,12,12,12,12,12,12,12,15,15,15,15,15,15,15,15,15,18,18,18,18,18,18,18,18,18,21,21,21,21,21,21,21,21,21,24,25,25,25,25,25,25 %N A279951 Expansion of Product_{k>=1} 1/(1 - x^((k*(k+1)/2)^2)). %C A279951 Number of partitions of n into nonzero squared triangular numbers (A000537). %H A279951 M. Bernstein and N. J. A. Sloane, <a href="http://arXiv.org/abs/math.CO/0205301">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version] %H A279951 M. Bernstein and N. J. A. Sloane, <a href="/A003633/a003633_1.pdf">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures] %H A279951 Wikipedia, <a href="https://en.wikipedia.org/wiki/Squared_triangular_number">Squared triangular number</a> %H A279951 <a href="/index/Par#partN">Index entries for related partition-counting sequences</a> %F A279951 G.f.: Product_{k>=1} 1/(1 - x^((k*(k+1)/2)^2)). %e A279951 a(10) = 2 because we have [9, 1] and [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]. %t A279951 nmax = 105; CoefficientList[Series[Product[1/(1 - x^((k (k + 1)/2)^2)), {k, 1, nmax}], {x, 0, nmax}], x] %Y A279951 Cf. A000537, A007294, A068980. %K A279951 nonn %O A279951 0,10 %A A279951 _Ilya Gutkovskiy_, Dec 23 2016