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 A379868 #13 Jan 05 2025 09:58:31
%S A379868 1,0,1,-1,25,-101,2281,-19895,472305,-6760297,177126121,-3578690435,
%T A379868 105341330953,-2743981145933,91092111623241,-2888769295882111,
%U A379868 107832291781283809,-4009180998104138321,167254334458983887689,-7105017992715364001147,328862774630320838523321
%N A379868 E.g.f. A(x) satisfies A(x) = exp(-x*A(x)^2) + x*A(x)^2.
%F A379868 E.g.f.: sqrt( (1/x) * Series_Reversion( x / (exp(-x) + x)^2 ) ).
%F A379868 a(n) = -n! * Sum_{k=0..n} (-2*n+k-1)^(n-k-1) * binomial(2*n,k)/(n-k)!.
%o A379868 (PARI) a(n) = -n!*sum(k=0, n, (-2*n+k-1)^(n-k-1)*binomial(2*n, k)/(n-k)!);
%Y A379868 Cf. A108919, A379871.
%Y A379868 Cf. A377859, A379879.
%Y A379868 Cf. A364982, A367866.
%K A379868 sign
%O A379868 0,5
%A A379868 _Seiichi Manyama_, Jan 04 2025