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 A349204 #8 Nov 15 2021 01:23:17 %S A349204 1,1,3,5,5,11,111,305,235,781,5733,22475,48065,217751,8527167, %T A349204 43899265,30286495,174772921,2148821763,13744073645,46580213525, %U A349204 327156548291,9697877988981,74211034240235,149247386387155,1236079055785861,21456247956983193,191231275195061015 %N A349204 a(n) = A065176(n + 2) * n! * [x^n](exp(x) / (1 + cos(x))). %F A349204 a(n) = 2^A007814(A052928(n+2))*n!*[x^n](exp(x) / (1 + cos(x))). %p A349204 # Using function A065176(n). %p A349204 egf := exp(x) / (1 + cos(x)): ser := series(egf, x, 30): %p A349204 seq(A065176(n+2)*n!*coeff(ser, x, n), n = 0..27); %Y A349204 Cf. A065176, A007814, A052928. %K A349204 nonn %O A349204 0,3 %A A349204 _Peter Luschny_, Nov 14 2021