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 A279222 #9 Feb 16 2025 08:33:37
%S A279222 1,1,1,1,1,1,1,2,2,2,2,2,2,2,3,3,3,3,3,3,3,4,5,5,5,5,5,5,6,7,7,7,7,7,
%T A279222 7,8,9,9,9,9,9,9,10,11,12,12,12,12,12,13,15,16,16,16,16,16,17,19,20,
%U A279222 20,20,20,20,21,23,24,25,25,25,25,26,28,30,31,31,31,31,32,34,36,37,37,37,37,38,40,42,43,44,44,44
%N A279222 Expansion of Product_{k>=1} 1/(1 - x^(k*(k+1)*(4*k-1)/6)).
%C A279222 Number of partitions of n into nonzero hexagonal pyramidal numbers (A002412).
%H A279222 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 A279222 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 A279222 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HexagonalPyramidalNumber.html">Hexagonal Pyramidal Number</a>
%H A279222 <a href="/index/Ps#pyramidal_numbers">Index to sequences related to pyramidal numbers</a>
%H A279222 <a href="/index/Par#partN">Index entries for related partition-counting sequences</a>
%F A279222 G.f.: Product_{k>=1} 1/(1 - x^(k*(k+1)*(4*k-1)/6)).
%e A279222 a(8) = 2 because we have [7, 1] and [1, 1, 1, 1, 1, 1, 1, 1].
%t A279222 nmax=90; CoefficientList[Series[Product[1/(1 - x^(k (k + 1) (4 k - 1)/6)), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A279222 Cf. A002412, A068980, A279220, A279221, A279223, A279224.
%K A279222 nonn
%O A279222 0,8
%A A279222 _Ilya Gutkovskiy_, Dec 08 2016