A083578 a(n) = (6^n + (-4)^n)/2.

1, 1, 26, 76, 776, 3376, 25376, 131776, 872576, 4907776, 30757376, 179301376, 1096779776, 6496792576, 39316299776, 234555621376, 1412702437376, 8454739787776, 50814338072576, 304542431051776, 1828628975845376

Offset: 0

Author

Paul Barry, Apr 30 2003

Keywords

• easy
• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (2,24).

Crossrefs

Cf. A083579. First differences of A051958.

Programs

Mathematica

LinearRecurrence[{2,24},{1,1},30] (* Harvey P. Dale, Nov 29 2017 *)

Formula

a(n) = (6^n + (-4)^n)/2.

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

E.g.f.: (exp(6x) + exp(-4x))/2.