A199308 a(n) = (7*5^n+1)/4.

2, 9, 44, 219, 1094, 5469, 27344, 136719, 683594, 3417969, 17089844, 85449219, 427246094, 2136230469, 10681152344, 53405761719, 267028808594, 1335144042969, 6675720214844, 33378601074219, 166893005371094, 834465026855469, 4172325134277344, 20861625671386719, 104308128356933594

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)-1.

a(n) = 6*a(n-1)-5*a(n-2).

G.f.: (2-3*x)/((1-x)*(1-5*x)).

Mathematica

(7*5^Range[0, 25] + 1)/4 (* Paolo Xausa, Mar 08 2026 *)

Prog

(Magma) [(7*5^n+1)/4: n in [0..30]];

Crossrefs

Sequence in context: A390194 A216861 A390528 * A383478 A387677 A176479

Adjacent sequences: A199305 A199306 A199307 * A199309 A199310 A199311

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 05 2011

Status

approved