A199018 a(n) = (3*11^n - 1)/2.

1, 16, 181, 1996, 21961, 241576, 2657341, 29230756, 321538321, 3536921536, 38906136901, 427967505916, 4707642565081, 51784068215896, 569624750374861, 6265872254123476, 68924594795358241, 758170542748940656, 8339875970238347221, 91738635672621819436, 1009124992398840013801

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..900

Index entries for linear recurrences with constant coefficients, signature (12,-11).

Formula

a(n) = 11*a(n-1) + 5.

a(n) = 12*a(n-1) - 11*a(n-2), n > 1.

G.f.: (1 + 4*x)/(1 - 12*x + 11*x^2). - Vincenzo Librandi, Jan 04 2013

From Elmo R. Oliveira, Apr 02 2025: (Start)

E.g.f.: exp(x)*(3*exp(10*x) - 1)/2.

a(n) = A199019(n)/2. (End)

Mathematica

(3*11^Range[0, 20]-1)/2 (* or *) LinearRecurrence[{12, -11}, {1, 16}, 20] (* Harvey P. Dale, Jul 16 2012 *)
CoefficientList[Series[(1 + 4*x)/(1 - 12*x + 11*x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 04 2013 *)

Prog

(Magma) [(3*11^n-1)/2 : n in [0..20]];

Crossrefs

Cf. A199019.

Sequence in context: A218895 A016909 A001455 * A204608 A279282 A231135

Adjacent sequences: A199015 A199016 A199017 * A199019 A199020 A199021

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 02 2011

Status

approved