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 A377946 #4 Nov 11 2024 22:29:21 %S A377946 1,1,2,10,40,136,512,2080,8320,32896,131072,524800,2099200,8390656, %T A377946 33554432,134225920,536903680,2147516416,8589934592,34359869440, %U A377946 137439477760,549756338176,2199023255552,8796095119360,35184380477440,140737496743936,562949953421312 %N A377946 Cogrowth sequence of the 16-element group C2^2:C4 = <S,T | S^4, T^2, (ST)^2, (S^2T)^2>. %C A377946 Gives the even terms, all the odd terms are 0. %C A377946 Also called K8:C2. Gap identifier 16, 3. %F A377946 G.f.: (12*x^4-14*x^3+8*x^2-5*x+1) / ((4*x-1) * (2*x-1) * (4*x^2+1)). %Y A377946 Cf. A377855 (C4:C4), A054879 (C2^3), A377843 (C4 X C2^2), A377943 (C4 o D4). %K A377946 nonn,easy %O A377946 0,3 %A A377946 _Sean A. Irvine_, Nov 11 2024