A144465 a(n) = 5^n - 2^(n - 1) for n > 0; a(0) = 1.

1, 4, 23, 121, 617, 3109, 15593, 78061, 390497, 1952869, 9765113, 48827101, 244138577, 1220699029, 6103507433, 30517561741, 152587857857, 762939387589, 3814697134553, 19073486065981, 95367431116337

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (8,-15).

Formula

From R. J. Mathar, Dec 08 2008: (Start)

a(n) = 7*a(n-1)-10*a(n-2), n > 3.

G.f.: (1-3*x+5*x^2)/((1-5*x)*(1-2*x)). [corrected by Vaclav Kotesovec, May 16 2021] (End)

Mathematica

Table[If [n == 0, 1, 5^n - 2^(n - 1)], {n, 0, 20}]

Crossrefs

Sequence in context: A297309 A201350 A015532 * A024050 A236421 A227639

Adjacent sequences: A144462 A144463 A144464 * A144466 A144467 A144468

Keyword

nonn,easy

Author

Roger L. Bagula, Oct 09 2008

Extensions

a(20) corrected by Georg Fischer, May 15 2021

Status

approved