A377943 Cogrowth sequence of the 16-element Pauli group C4 o D4 = <S,T,U | s^4, T^2, U^2, S^2(TU)^2, [S,T], [S,U]>.

1, 1, 11, 91, 821, 7381, 66431, 597871, 5380841, 48427561, 435848051, 3922632451, 35303692061, 317733228541, 2859599056871, 25736391511831, 231627523606481, 2084647712458321, 18761829412124891, 168856464709124011, 1519708182382116101, 13677373641439044901

Offset

0,3

Comments

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

Links

Table of n, a(n) for n=0..21.

Index entries for linear recurrences with constant coefficients, signature (9, 1, -9).

Formula

G.f.: (x^2-8*x+1) / ((x-1) * (9*x-1) * (x+1)).

Crossrefs

Cf. A070775 (C4 X C4), A377855 (C4:C4), A047854 (D4 X C2).

Sequence in context: A126532 A226868 A199678 * A201549 A117611 A294362

Adjacent sequences: A377940 A377941 A377942 * A377944 A377945 A377946

Keyword

nonn,easy

Author

Sean A. Irvine, Nov 11 2024

Status

approved