A133667 a(n) = a(n-1) - 25*a(n-2), a(0)=1, a(1)=5.

1, 5, -20, -145, 355, 3980, -4895, -104395, 17980, 2627855, 2178355, -63518020, -117976895, 1469973605, 4419395980, -32329944145, -142814843645, 665433759980, 4235804851105, -12400039148395, -118295160426020, 191705818283855

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Index entries for linear recurrences with constant coefficients, signature (1,-25).

Formula

G.f.: (1+4*x)/(1-x+25*x^2).

a(n) = Sum_{k=0..n} A133607(n,k)*5^k. - Philippe Deléham, Dec 29 2007

Mathematica

LinearRecurrence[{1, -25}, {1, 5}, 22] (* Georg Fischer, May 02 2019 *)

Prog

(PARI) Vec((1+4*x)/(1-x+25*x^2) + O(x^30)) \\ Michel Marcus, May 02 2019

Crossrefs

Cf. A133607.

Sequence in context: A024066 A009569 A061964 * A354848 A318433 A205338

Adjacent sequences: A133664 A133665 A133666 * A133668 A133669 A133670

Keyword

easy,sign

Author

Philippe Deléham, Dec 28 2007

Extensions

a(10) corrected by Georg Fischer, May 02 2019

Status

approved