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 A377840 #8 Nov 10 2024 20:41:15 %S A377840 1,1,1,1,2,46,496,3004,12872,43912,130816,394384,1470944,6874336, %T A377840 33550336,151869376,622116992,2353246336,8589869056,31961192704, %U A377840 125858012672,521796316672,2199022206976,9122012806144,36758056208384,144536687773696,562949936644096 %N A377840 Cogrowth sequence of the 16-element group C8 X C2 = <S,T | S^8, T^2, [S,T]>. %C A377840 Gives the even terms, all the odd terms are 0. %H A377840 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (8,-28,56,-68,112,112,64). %F A377840 G.f.: (8*x^7+28*x^6+42*x^5-34*x^4+35*x^3-21*x^2+7*x-1) / ((4*x-1) * (4*x^2+1) * (4*x^4+8*x^3+8*x^2-4*x+1)). %e A377840 a(4)=2 corresponds to the words SSSSSSSS and TTTTTTTT. %Y A377840 Cf. A007582 (D8), A377627 (C6 X C2), A377714 (C4 X C2). %K A377840 nonn,easy %O A377840 0,5 %A A377840 _Sean A. Irvine_, Nov 09 2024