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A215109 a(n) = A215082(2*n+1) 0
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 20 20:24 EDT 2019. Contains 328273 sequences. (Running on oeis4.)