A133479 - OEIS

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

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..24.

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

CROSSREFS

Sequence in context: A322201 A099583 A328743 * A196324 A327841 A196648

Adjacent sequences: A133476 A133477 A133478 * A133480 A133481 A133482

KEYWORD

easy,nonn

AUTHOR

Philippe Deléham, Jan 03 2008

STATUS

approved