A146884 a(n) = 7*Sum_{k=0..n} 6^k.

7, 49, 301, 1813, 10885, 65317, 391909, 2351461, 14108773, 84652645, 507915877, 3047495269, 18284971621, 109709829733, 658258978405, 3949553870437, 23697323222629, 142183939335781, 853103636014693, 5118621816088165

Offset

0,1

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (7,-6).

Formula

From G. C. Greubel, Oct 12 2022: (Start)

a(n) = (7/5)*(6^(n+1) - 1).

a(n) = 7*A003464(n+1).

a(n) = 7*a(n-1) - 6*a(n-2).

G.f.: 7/((1-x)*(1-6*x)).

E.g.f.: (7/5)*(6*exp(6*x) - exp(x)). (End)

Mathematica

a[n_]:= Sum[7*6^m, {m, 0, n}]; Table[a[n], {n, 0, 30}]
Accumulate[7*6^Range[0, 20]] (* Harvey P. Dale, Dec 18 2021 *)

Prog

(Magma) [n le 2 select 7^n else 7*Self(n-1) -6*Self(n-2): n in [1..31]]; // G. C. Greubel, Oct 12 2022
(SageMath) [(7/5)*(6^(n+1)-1) for n in range(41)] # G. C. Greubel, Oct 12 2022

Crossrefs

Cf. A003464, A005843, A068156, A100774, A132583, A146882, A146883, A146885.

Sequence in context: A189258 A188748 A188986 * A113235 A294261 A294293

Adjacent sequences: A146881 A146882 A146883 * A146885 A146886 A146887

Keyword

nonn,easy,less

Author

Roger L. Bagula, Nov 02 2008

Status

approved