A113968 a(0) = 0 and a(n) = (5*(-4)^n + 16*(-1)^n + 9*4^n)/240 for n >= 1.

0, 0, 1, 1, 15, 17, 239, 273, 3823, 4369, 61167, 69905, 978671, 1118481, 15658735, 17895697, 250539759, 286331153, 4008636143, 4581298449, 64138178287, 73300775185, 1026210852591, 1172812402961, 16419373641455, 18764998447377

Offset: 0

Author

Roger L. Bagula, Jan 31 2006

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (-1,16,16).

Crossrefs

Cf. A112627.

Programs

Mathematica

a[n_] := If[n == 0, 1, (5(-4)^n + 16(-1)^n + 9*4^n) / 240];
a /@ Range[0, 25] (* Jean-François Alcover, Mar 30 2021 *)

Formula

From Colin Barker, Dec 03 2012: (Start)

a(n) = (5*(-4)^n + 16*(-1)^n + 9*4^n)/240 for n>0.

G.f.: -x^2*(2*x+1) / ((x+1)*(4*x-1)*(4*x+1)). (End)

Extensions

New name (using Colin Barker's formula) from Joerg Arndt, Aug 30 2022