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 A373221 #14 May 31 2024 14:35:50
%S A373221 1,1,1,2,2,3,4,6,7,9,12,14,18,22,28,34,41,50,60,72,86,105,124,146,174,
%T A373221 204,240,282,332,386,450,524,606,703,812,940,1082,1243,1428,1636,1873,
%U A373221 2140,2448,2788,3172,3610,4096,4646,5264,5963,6737,7607,8584,9668,10887,12244,13765,15451,17328
%N A373221 Expansion of Product_{i>=1, j>=0} (1 + x^(i * 7^j)).
%C A373221 This sequence is different from A093950. The first difference occurs at a(50) = 6737, whereas A093950(50) = 6736.
%F A373221 G.f.: Product_{k>=1} (1 + x^k)^A373217(k).
%F A373221 Let A(x) be the g.f. of this sequence, and B(x) be the g.f. of A000009, then B(x) = A(x)/A(x^7).
%o A373221 (PARI) my(N=60, x='x+O('x^N)); Vec(prod(k=1, N, (1+x^k)^(valuation(k, 7)+1)))
%Y A373221 Cf. A000041, A174065, A327726, A373219, A373220.
%Y A373221 Cf. A000009, A093950, A373217.
%K A373221 nonn
%O A373221 0,4
%A A373221 _Seiichi Manyama_, May 28 2024