OFFSET
1,2
REFERENCES
F. Faase, On the number of specific spanning subgraphs of the graphs G X P_n, Ars Combin. 49 (1998), 129-154.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
F. Faase, On the number of specific spanning subgraphs of the graphs G X P_n, Preliminary version of paper that appeared in Ars Combin. 49 (1998), 129-154.
F. Faase, Results from the counting program
Index entries for linear recurrences with constant coefficients, signature (9,-4,-22,3).
FORMULA
a(n) = 9a(n-1) - 4a(n-2) - 22a(n-3) + 3a(n-4), n>4.
G.f.: -x*(3*x^3-14*x^2+2*x+1)/(3*x^4-22*x^3-4*x^2+9*x-1). - Colin Barker, Aug 30 2012
MATHEMATICA
CoefficientList[Series[-(3 x^3 - 14 x^2 + 2 x + 1)/(3 x^4 - 22 x^3 - 4 x^2 + 9 x - 1), {x, 0, 40}], x] (* Vincenzo Librandi, Oct 13 2013 *)
LinearRecurrence[{9, -4, -22, 3}, {1, 11, 81, 666}, 30] (* Harvey P. Dale, Sep 23 2016 *)
PROG
(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; 3, -22, -4, 9]^(n-1)*[1; 11; 81; 666])[1, 1] \\ Charles R Greathouse IV, Jun 23 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved