A198856 a(n) = 9*8^n - 1.

8, 71, 575, 4607, 36863, 294911, 2359295, 18874367, 150994943, 1207959551, 9663676415, 77309411327, 618475290623, 4947802324991, 39582418599935, 316659348799487, 2533274790395903, 20266198323167231, 162129586585337855

Offset

0,1

Comments

The subsequence of primes begins: 71, 294911, 18874367, 83010348331692982271, no more through a(30). - Jonathan Vos Post, Oct 31 2011

Links

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

Index entries for linear recurrences with constant coefficients, signature (9,-8).

Formula

a(n) = 8*a(n-1) + 7.

a(n) = 9*a(n-1) - 8*a(n-2), n>1.

G.f.: (8-x)/((1-x)*(1-8*x)). - Vincenzo Librandi, Oct 04 2014

E.g.f.: exp(x)*(9*exp(7*x) - 1). - Elmo R. Oliveira, Aug 10 2024

Mathematica

CoefficientList[Series[(8 - x)/((1-x) (1 - 8 x)), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 04 2014 *)
LinearRecurrence[{9, -8}, {8, 71}, 20] (* Harvey P. Dale, Aug 26 2020 *)

Prog

(Magma) [9*8^n-1: n in [0..30]];

Crossrefs

Sequence in context: A217328 A193102 A038145 * A320092 A015576 A070998

Adjacent sequences: A198853 A198854 A198855 * A198857 A198858 A198859

Keyword

nonn,easy

Author

Vincenzo Librandi, Oct 31 2011

Status

approved