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 A345749 #21 Feb 16 2025 08:34:02 %S A345749 1,1,4,21,147,1250,12633,147497,1947676,28699373,466994003,8309274754, %T A345749 160368858609,3336869582657,74468098634660,1773827462044421, %U A345749 44905503103938915,1203843692164105458,34070243272290551113,1015056385225183643721 %N A345749 E.g.f.: Product_{k>=1} 1/(1 - (exp(x) - 1)^k)^(1/k). %C A345749 Stirling transform of A028342. %H A345749 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a> %H A345749 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/StirlingTransform.html">Stirling Transform</a> %F A345749 E.g.f.: exp( Sum_{k>=1} d(k) * (exp(x) - 1)^k / k ), where d(n) is the number of divisors of n. %F A345749 a(n) = Sum_{k=0..n} Stirling2(n,k) * A028342(k). %t A345749 max = 19; Range[0, max]! * CoefficientList[Series[Product[1/(1 - (Exp[x] - 1)^k)^(1/k), {k, 1, max}], {x, 0, max}], x] (* _Amiram Eldar_, Jun 26 2021 *) %o A345749 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/prod(k=1, N, (1-(exp(x)-1)^k)^(1/k)))) %o A345749 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, N,numdiv(k)*(exp(x)-1)^k/k)))) %Y A345749 Cf. A000005, A028342, A048993, A167137, A294363, A305986, A345750, A345751. %K A345749 nonn %O A345749 0,3 %A A345749 _Seiichi Manyama_, Jun 26 2021