A178671 a(n) = 5^n - 5.

-4, 0, 20, 120, 620, 3120, 15620, 78120, 390620, 1953120, 9765620, 48828120, 244140620, 1220703120, 6103515620, 30517578120, 152587890620, 762939453120, 3814697265620, 19073486328120, 95367431640620, 476837158203120, 2384185791015620, 11920928955078120

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (6,-5).

Formula

a(n) = 5*a(n-1) + 20 with a(0) = -4.

From R. J. Mathar, Jan 03 2011: (Start)

G.f.: 4*(-1+6*x)/((1-5*x)*(1-x)).

a(n) = 4*A104891(n-1), n > 0. (End)

a(n) = 6*a(n-1) - 5*a(n-2) for n > 1. - Vincenzo Librandi, Jan 25 2013

E.g.f.: exp(5*x) - 5*exp(x). - G. C. Greubel, Jan 28 2019

Example

a(n) = A178676(n)-10 = A242329(n)-9 = A242328(n)-7 = A034474(n)-6 = A000351(n)-5. - Elmo R. Oliveira, Dec 06 2023

Mathematica

5^Range[0, 30]-5 (* Vladimir Joseph Stephan Orlovsky, Feb 20 2011 *)
LinearRecurrence[{6, -5}, {-4, 0}, 30] (* Harvey P. Dale, Aug 23 2024 *)

Prog

(Magma) [5^n-5: n in [0..25]];
(PARI) vector(30, n, n--; 5^n-5) \\ G. C. Greubel, Jan 28 2019
(Sage) [5^n-5 for n in range(30)] # G. C. Greubel, Jan 28 2019
(GAP) List([0..30], n -> 5^n-5); # G. C. Greubel, Jan 28 2019

Crossrefs

Cf. A000351, A034474, A178676, A242328, A242329.

Sequence in context: A286032 A199933 A078630 * A076021 A179270 A246132

Adjacent sequences: A178668 A178669 A178670 * A178672 A178673 A178674

Keyword

sign,easy

Author

Vincenzo Librandi, Dec 25 2010

Status

approved