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 A369578 #11 Apr 15 2025 09:30:05 %S A369578 1,1,2,5,13,33,81,194,458,1074,2513,5876,13722,31961,74168,171395, %T A369578 394450,904393,2066770,4709538,10704306,24273709,54926658,124036675, %U A369578 279559571,628906790,1412254773,3165780760,7084607367,15828666526,35309625162,78648201835,174927430681 %N A369578 a(n) = [x^n] Product_{j=1..n, k=1..n} (1 + x^(k^j)). %H A369578 Vaclav Kotesovec, <a href="/A369578/b369578.txt">Table of n, a(n) for n = 0..1000</a> %t A369578 Table[SeriesCoefficient[Product[Product[1 + x^(k^j), {k, 1, n^(1/j)}], {j, 1, n}], {x, 0, n}], {n, 0, 40}] %Y A369578 Cf. A000009, A033461, A279329, A369575, A369570. %K A369578 nonn %O A369578 0,3 %A A369578 _Vaclav Kotesovec_, Jan 26 2024