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 A378254 #6 Nov 20 2024 20:44:06 %S A378254 1,1,1,1,1,2,67,1002,8009,43759,184758,646878,1971883,5541966, %T A378254 16231216,60090032,290305577,1523150157,7564006759,34099637859, %U A378254 139541849878,526321168143,1878476551128,6603812572941,24052434515891,94278969044262,396750746960712 %N A378254 Cogrowth sequence of the 20-element group C10 X C2 = <S,T | S^10, T^2, [S,T]>. %C A378254 Gives the even terms, all the odd terms are 0. %F A378254 G.f.: (10*x^9+75*x^8+162*x^7-48*x^6+127*x^5-126*x^4+84*x^3-36*x^2+9*x-1) / ((4*x-1) * (25*x^4+10*x^2-5*x+1) * (x^4+4*x^3+6*x^2-x+1)). %Y A378254 Cf. A377840 (C8 X C2), A377627 (C6 X C2), A078789 (D10). %K A378254 nonn,easy %O A378254 0,6 %A A378254 _Sean A. Irvine_, Nov 20 2024