A024872 a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers >= 2), t = (Fibonacci numbers).

2, 4, 12, 19, 43, 70, 138, 223, 409, 662, 1162, 1880, 3210, 5194, 8710, 14093, 23353, 37786, 62118, 100509, 164355, 265932, 433316, 701120, 1139714, 1844096, 2992960, 4842711, 7851463, 12703934, 20582546, 33303259, 53932317, 87264322

Offset

2,1

Links

Table of n, a(n) for n=2..35.

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

Formula

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

Crossrefs

Sequence in context: A309632 A309659 A309664 * A129021 A290440 A090922

Adjacent sequences: A024869 A024870 A024871 * A024873 A024874 A024875

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from James A. Sellers, May 03 2000

Status

approved