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 A331339 #8 Aug 20 2021 05:44:19 %S A331339 1,1,5,32,292,3294,44918,714468,13002456,266275200,6060498672, %T A331339 151750887936,4145522908272,122690391196944,3910569680464848, %U A331339 133549150323123744,4864927063250290176,188297220693251438208,7716800776602560577408 %N A331339 E.g.f.: 1 / (1 + log(1 - x - x^2)). %F A331339 a(0) = 1; a(n) = Sum_{k=1..n} binomial(n,k) * (k - 1)! * Lucas(k) * a(n-k). %F A331339 a(n) ~ n! * 2^(n+1) * exp(n/2) / (sqrt(5*exp(1) - 4) * (sqrt(5*exp(1) - 4) - exp(1/2))^(n+1)). - _Vaclav Kotesovec_, Jan 26 2020 %p A331339 A331339 := proc(n) %p A331339 option remember; %p A331339 if n = 0 then %p A331339 1; %p A331339 else %p A331339 add(binomial(n,k)*(k-1)!*A000204(k)*procname(n-k),k=1..n) ; %p A331339 end if; %p A331339 end proc: %p A331339 seq(A331339(n),n=0..42) ; # _R. J. Mathar_, Aug 20 2021 %t A331339 nmax = 18; CoefficientList[Series[1/(1 + Log[1 - x - x^2]), {x, 0, nmax}], x] Range[0, nmax]! %t A331339 a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, k] (k - 1)! LucasL[k] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 18}] %Y A331339 Cf. A000204, A007840, A039647. %K A331339 nonn %O A331339 0,3 %A A331339 _Ilya Gutkovskiy_, Jan 14 2020