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 A356795 #21 Feb 16 2025 08:34:03 %S A356795 1,0,2,3,68,330,7674,73080,1883440,28281960,818625960,17120406600, %T A356795 557507325000,15014517495120,548643259812816,18056683281775320, %U A356795 736892260092195840,28579282973977498560,1295028345251832359616,57666859088090317591680 %N A356795 E.g.f. satisfies A(x) = 1/(1 - x)^(x * A(x)^2). %H A356795 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LambertW-Function.html">Lambert W-Function</a>. %F A356795 a(n) = n! * Sum_{k=0..floor(n/2)} (2*k+1)^(k-1) * |Stirling1(n-k,k)|/(n-k)!. %F A356795 E.g.f.: A(x) = Sum_{k>=0} (2*k+1)^(k-1) * (-x * log(1-x))^k / k!. %F A356795 E.g.f.: A(x) = exp( -LambertW(2 * x * log(1-x))/2 ). %F A356795 E.g.f.: A(x) = ( LambertW(2 * x * log(1-x))/(2 * x * log(1-x)) )^(1/2). %o A356795 (PARI) a(n) = n!*sum(k=0, n\2, (2*k+1)^(k-1)*abs(stirling(n-k, k, 1))/(n-k)!); %o A356795 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, (2*k+1)^(k-1)*(-x*log(1-x))^k/k!))) %o A356795 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(-lambertw(2*x*log(1-x))/2))) %o A356795 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace((lambertw(2*x*log(1-x))/(2*x*log(1-x)))^(1/2))) %Y A356795 Cf. A066166, A355842, A356796. %Y A356795 Cf. A356786. %K A356795 nonn %O A356795 0,3 %A A356795 _Seiichi Manyama_, Aug 28 2022