A107248 a(n) = 4*a(n-2) - 4*a(n-4) + 25*a(n-6).

1, 1, 1, 37, 37, 169, 169, 553, 553, 2461, 2461, 11857, 11857, 51409, 51409, 219733, 219733, 969721, 969721, 4285177, 4285177, 18755149, 18755149, 82122913, 82122913, 360600481, 360600481, 1582788997, 1582788997, 6941826889

Offset

0,4

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0, 4, 0, -4, 0, 25).

Formula

From R. J. Mathar, Jul 03 2009: (Start)

a(n) = 4*a(n-2) - 4*a(n-4) + 25*a(n-6).

G.f.: -(1+x-3*x^2+33*x^3+37*x^4+25*x^5)/((5*x^3-2*x^2+1)*(5*x^3+2*x^2-1)).

(End)

Mathematica

CoefficientList[Series[-(1 + x - 3 x^2 + 33 x^3 + 37 x^4 + 25 x^5)/((5 x^3 - 2 x^2 + 1) (5 x^3 + 2 x^2 - 1)), {x, 0, 29}], x] (* Michael De Vlieger, Feb 20 2018 *)
LinearRecurrence[{0, 4, 0, -4, 0, 25}, {1, 1, 1, 37, 37, 169}, 30] (* Vincenzo Librandi, Feb 21 2018 *)

Prog

(Magma) I:=[1, 1, 1, 37, 37, 169]; [n le 6 select I[n] else 4*Self(n-2)-4*Self(n-4)+25*Self(n-6): n in [1..40]]; // Vincenzo Librandi, Feb 21 2018

Crossrefs

Cf. A007493.

Sequence in context: A291478 A257810 A090179 * A219402 A219450 A165858

Adjacent sequences: A107245 A107246 A107247 * A107249 A107250 A107251

Keyword

nonn,easy,less

Author

Roger L. Bagula, Jun 08 2005

Extensions

Edited by N. J. A. Sloane, May 13 2006

New name using Mathar's recurrence from Joerg Arndt, Feb 20 2018

Status

approved