A199757 a(n) = (7*11^n+1)/2.

4, 39, 424, 4659, 51244, 563679, 6200464, 68205099, 750256084, 8252816919, 90780986104, 998590847139, 10984499318524, 120829492503759, 1329124417541344, 14620368592954779, 160824054522502564, 1769064599747528199

Offset

0,1

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).

G.f.: (4-9*x)/((1-x)*(1-11*x)).

E.g.f.: exp(x)*(1 + 7*exp(10*x))/2. - Stefano Spezia, Jun 01 2026

Mathematica

(7*11^Range[0, 20]+1)/2 (* Harvey P. Dale, Dec 30 2017 *)
(* Alternative: *)
LinearRecurrence[{12, -11}, {4, 39}, 20] (* Harvey P. Dale, Dec 30 2017 *)

Prog

(Magma) [(7*11^n+1)/2: n in [0..30]];

Crossrefs

Cf. A001020.

Sequence in context: A241075 A396580 A123618 * A046449 A203211 A214823

Adjacent sequences: A199754 A199755 A199756 * A199758 A199759 A199760

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 10 2011

Status

approved