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 A280253 #10 Feb 16 2025 08:33:38
%S A280253 1,1,1,2,1,2,2,2,3,2,3,3,3,3,3,4,4,4,5,4,4,5,5,6,5,6,6,6,6,6,7,6,7,8,
%T A280253 7,7,8,8,9,8,9,9,9,10,9,11,9,10,12,10,11,11,11,12,11,12,13,13,14,14,
%U A280253 14,13,13,15,15,14,15,15,15,15,15,16,16,16,17,17,15,17,19,19,20,19,20,20,19,21,20,20,21,21,22
%N A280253 Expansion of Product_{k>=1} (1 + x^p(k)), where p(k) is the number of partitions of k (A000041).
%C A280253 Number of partitions of n into distinct partition numbers.
%H A280253 Alois P. Heinz, <a href="/A280253/b280253.txt">Table of n, a(n) for n = 0..20000</a>
%H A280253 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 A280253 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 A280253 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PartitionFunctionP.html">Partition Function P</a>, <a href="https://mathworld.wolfram.com/PartitionFunctionQ.html">Partition Function Q</a>
%H A280253 <a href="/index/Par#partN">Index entries for related partition-counting sequences</a>
%F A280253 G.f.: Product_{k>=1} (1 + x^p(k)).
%e A280253 a(8) = 3 because we have [7, 1], [5, 3] and [5, 2, 1].
%t A280253 nmax = 90; CoefficientList[Series[Product[(1 + x^PartitionsP[k]), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A280253 Cf. A000009, A000041, A007279, A086209.
%K A280253 nonn
%O A280253 0,4
%A A280253 _Ilya Gutkovskiy_, Dec 30 2016