A377885 - OEIS

%I #7 Nov 12 2024 12:17:47

%S 1,1,1,4,28,136,544,2080,8128,32512,130816,524800,2099200,8390656,

%T 33550336,134201344,536854528,2147516416,8590065664,34359869440,

%U 137438691328,549754765312,2199022206976,8796095119360,35184380477440,140737496743936,562949936644096

%N Cogrowth sequence of the 16-element quasihedral group SD16 = <S,T | S^8, T^2, STS^5T>.

%C Gives the even terms, all the odd terms are 0.

%C Also called QD16, Q8:C2. Gap identifier 16,8.

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (6, -12, 16).

%F G.f.: (6*x^3-7*x^2+5*x-1) / ((4*x-1) * (4*x^2-2*x+1)).

%Y Cf. A047849 (D4), A007582 (D8), A071930 (Q8), A377840 (C8 X C2), A377883 (M4(2)).

%K nonn,easy

%O 0,4

%A _Sean A. Irvine_, Nov 10 2024