A024878 - OEIS

A024878

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

6, 9, 27, 44, 96, 155, 299, 484, 874, 1414, 2456, 3974, 6736, 10899, 18185, 29424, 48588, 78617, 128933, 208618, 340580, 551070, 896928, 1451260, 2357338, 3814253, 6187383, 10011396, 16225928, 26254103, 42526543, 68809392, 111415374, 180273862, 291824536, 472182018

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OFFSET

2,1

LINKS

Table of n, a(n) for n=2..37.

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

FORMULA

G.f.: x^2*(1+x)*(2*x^6+4*x^4+x^3-3*x^2+3*x-6)/ ((x^2+x-1) * (x^4+x^2-1)^2). - Maksym Voznyy (voznyy(AT)mail.ru), Jul 28 2009

MATHEMATICA

CoefficientList[Series[x^2*(1+x)*(2*x^6+4*x^4+x^3-3*x^2+3*x-6)/ ((x^2+x-1) * (x^4+x^2-1)^2), {x, 0, 40}], x] (* Stefano Spezia, Nov 21 2025 *)

CROSSREFS

Sequence in context: A115644 A243708 A300345 * A007414 A274977 A340630