A215109 a(n) = A215082(2*n+1).

1, 3, 5, 12, 23, 43, 81, 148, 266, 476, 842, 1478, 2581, 4481, 7743, 13328, 22857, 39073, 66605, 113242, 192084, 325128, 549252, 926220, 1559353, 2621295, 4400249, 7376868, 12352043, 20659159, 34516377

Offset

0,2

Links

Table of n, a(n) for n=0..30.

Index entries for linear recurrences with constant coefficients, signature (1,2,1,-2,-3,-1).

Formula

a(n) = a(n-1) + 2*a(n-2) + a(n-3) - 2*a(n-4) - 3*a(n-5) - a(n-6), a(0) = 1, a(1) = 3, a(2) = 5, a(3) = 12, a(4) = 23, a(5) = 43.

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

Crossrefs

Cf. A000045, A023607, A215082, A215108.

Sequence in context: A161624 A247794 A034758 * A131322 A224747 A036657

Adjacent sequences: A215106 A215107 A215108 * A215110 A215111 A215112

Keyword

nonn,easy

Author

Philippe Deléham, Aug 03 2012

Status

approved