A025106 - OEIS

A025106

a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (F(2), F(3), F(4), ...), t = (odd natural numbers).

3, 5, 17, 23, 50, 62, 119, 141, 251, 289, 496, 560, 939, 1045, 1729, 1903, 3122, 3406, 5559, 6021, 9795, 10545, 17120, 18336, 29731, 31701, 51361, 54551, 88338, 93502, 151367, 159725, 258523, 272049, 440272, 462160, 747883, 783301, 1267505, 1324815, 2143698

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..41.

Index entries for linear recurrences with constant coefficients, signature (2,1,-4,3,-2,-1,4,-3,2,-1).

FORMULA

G.f.: x*(3-x+4*x^2-4*x^3-2*x^4-2*x^5-x^6-x^7)/ ((x-1)^2*(x^4+x^2-1)^2) [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 27 2009]

MATHEMATICA

LinearRecurrence[{2, 1, -4, 3, -2, -1, 4, -3, 2, -1}, {3, 5, 17, 23, 50, 62, 119, 141, 251, 289}, 50] (* Harvey P. Dale, Sep 15 2024 *)

CROSSREFS

Sequence in context: A231232 A154608 A024862 * A333199 A203193 A079649