cp's OEIS Frontend

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.

A379859 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(x) * (1 - x*exp(x))^2 ).

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%I A379859 #13 Jan 05 2025 09:58:57
%S A379859 1,1,9,110,2121,53834,1720105,66197578,2984752113,154358553986,
%T A379859 9009411908001,585917934419498,42018536835853369,3294423846094650658,
%U A379859 280362373171289449209,25739124908062020925034,2535728977438902352557921,266836955238122741966767874,29872121613650590137264191665
%N A379859 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(x) * (1 - x*exp(x))^2 ).
%H A379859 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A379859 E.g.f. A(x) satisfies A(x) = exp(-x*A(x))/(1 - x * A(x) * exp(x*A(x)))^2.
%F A379859 a(n) = (n!/(n+1)) * Sum_{k=0..n} (-n+k-1)^(n-k) * binomial(2*n+k+1,k)/(n-k)!.
%o A379859 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(serreverse(x*exp(x)*(1-x*exp(x))^2)/x))
%o A379859 (PARI) a(n) = n!*sum(k=0, n, (-n+k-1)^(n-k)*binomial(2*n+k+1, k)/(n-k)!)/(n+1);
%Y A379859 Cf. A377546, A379860.
%Y A379859 Cf. A379684.
%K A379859 nonn
%O A379859 0,3
%A A379859 _Seiichi Manyama_, Jan 04 2025