OFFSET
0,4
COMMENTS
See the M. Bruschi et al. reference given in A129467.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..250
FORMULA
a(n) = Sum_{j=0..n} A129467(n,j), n >= 0.
a(n) = Sum_{j=0..n-1} A130559(n, j), n>= 1.
From Vaclav Kotesovec, Aug 24 2016: (Start)
a(n) = (-1)^n*Product_{k=1..n} (k^2 - k - 1).
a(n) ~ 2*(-1)^n * cos(sqrt(5)*Pi/2) * n^(2*n) / exp(2*n). (End)
a(n) + (n^2-n-1)*a(n-1) = 0. - R. J. Mathar, Jan 21 2018
MATHEMATICA
Table[(-1)^n*Product[k^2-k-1, {k, 1, n}], {n, 0, 20}] (* Vaclav Kotesovec, Aug 24 2016 *)
Table[FullSimplify[(-1)^n * Cos[Sqrt[5]*Pi/2] * Gamma[n+(Sqrt[5]+1)/2] * Gamma[n-(Sqrt[5]-1)/2]/Pi], {n, 0, 20}] (* Vaclav Kotesovec, Aug 24 2016 *)
PROG
(Magma) [1] cat [n le 1 select 1 else -(n^2-n-1)*Self(n-1): n in [1..30]]; // G. C. Greubel, Feb 10 2024
(SageMath)
[A130031(n) for n in range(31)] # G. C. Greubel, Feb 10 2024
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Wolfdieter Lang, May 04 2007
STATUS
approved