A024877 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 = (Lucas numbers).

9, 12, 37, 61, 133, 214, 413, 669, 1208, 1954, 3394, 5492, 9309, 15062, 25131, 40663, 67147, 108646, 178181, 288303, 470670, 761560, 1239524, 2005592, 3257761, 5271168, 8550753

Offset

2,1

Links

Table of n, a(n) for n=2..28.

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

Formula

G.f.: x^2*(-9+4*x^7+2*x^6+7*x^5+6*x^4-6*x^3+2*x^2-3*x) /((x^2+x-1)*(x^4+x^2-1)^2) [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 28 2009]

Mathematica

LinearRecurrence[{1, 3, -2, -1, -1, -3, 2, 1, 1, 1}, {9, 12, 37, 61, 133, 214, 413, 669, 1208, 1954}, 30] (* Harvey P. Dale, Jan 23 2017 *)

Crossrefs

Sequence in context: A195162 A216297 A024312 * A120991 A253088 A341208

Adjacent sequences: A024874 A024875 A024876 * A024878 A024879 A024880

Keyword

nonn

Author

Clark Kimberling

Status

approved