A133479 a(n) = a(n-1) + 8*a(n-2) for n >= 2, a(0)=1, a(1)=2.
1, 2, 10, 26, 106, 314, 1162, 3674, 12970, 42362, 146122, 485018, 1653994, 5534138, 18766090, 63039194, 213167914, 717481466, 2422824778, 8162676506, 27545274730, 92846686778, 313208884618, 1055982378842, 3561653455786
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (1,8).
Formula
G.f.: (1+x)/(1-x-8*x^2).
a(n) = Sum_{k=0..n+1} A122950(n+1,k)*7^(n+1-k). - Philippe Deléham, Jan 08 2008
a(n) = ((11+sqrt(33))/22)*(1/2 + (1/2)*sqrt(33))^n + ((11-sqrt(33))/22)*(1/2 - (1/2)*sqrt(33))^n. - Richard Choulet, Nov 20 2008