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 A081163 #8 Jan 11 2024 09:18:03 %S A081163 0,0,0,1,4,15,56,185,655 %N A081163 Number of even cycles in range [A014137(2n)..A014138(2n)] of permutation A057505/A057506, with two fixed-points of A057163. %F A081163 a(n) = A081162(2n+1) = (A000108(n) - A081156(n))/2. %Y A081163 Cf. A081162, A000108, A081156. %Y A081163 Cf. A014137, A014138, A057505, A057506, A057163. %K A081163 nonn,more %O A081163 0,5 %A A081163 _Wouter Meeussen_ and _Antti Karttunen_, Mar 10 2003