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 A381414 #11 Feb 23 2025 08:16:51
%S A381414 1,2,4,6,-32,-686,-8256,-72394,-200448,11160866,373370880,7696016614,
%T A381414 100295200768,-338643776142,-77999443329024,-3211092423560938,
%U A381414 -85537972638318592,-1169784729390416830,33029632126142382080,3381750252027454249926,158090250687453045194752
%N A381414 E.g.f. A(x) satisfies A(x) = exp( 2 * sin(x * A(x)) / A(x) ).
%F A381414 E.g.f.: B(x)^2, where B(x) is the e.g.f. of A381413.
%F A381414 a(n) = 2 * Sum_{k=0..n} (2*n-2*k+2)^(k-1) * i^(n-k) * A136630(n,k), where i is the imaginary unit.
%o A381414 (PARI) a136630(n, k) = 1/(2^k*k!)*sum(j=0, k, (-1)^(k-j)*(2*j-k)^n*binomial(k, j));
%o A381414 a(n) = 2*sum(k=0, n, (2*n-2*k+2)^(k-1)*I^(n-k)*a136630(n, k));
%Y A381414 Cf. A136630, A381413.
%K A381414 sign
%O A381414 0,2
%A A381414 _Seiichi Manyama_, Feb 23 2025