A015603 a(n) = 11*a(n-1) + 9*a(n-2).

0, 1, 11, 130, 1529, 17989, 211640, 2489941, 29294111, 344644690, 4054738589, 47703926689, 561235840880, 6602929589881, 77683348056611, 913943194931650, 10752525276757649, 126503266798718989, 1488308662276727720, 17509924686232475821

Offset: 0

Author

Olivier Gérard

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..900
• Index entries for linear recurrences with constant coefficients, signature (11,9).

Programs

Magma

[n le 2 select n-1 else 11*Self(n-1) + 9*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Nov 22 2012

Mathematica

Join[{a=0,b=1},Table[c=11*b+9*a;a=b;b=c,{n,60}]] (* Vladimir Joseph Stephan Orlovsky, Jan 31 2011 *)
LinearRecurrence[{11, 9}, {0, 1}, 30] (* Vincenzo Librandi, Nov 22 2012 *)

PARI

x='x+O('x^30); concat([0], Vec(x/(1-11*x-9*x^2))) \\ G. C. Greubel, Jan 16 2018

Sage

[lucas_number1(n,11,-9) for n in range(0, 18)] # Zerinvary Lajos, Apr 27 2009

Formula

G.f.: x/(1 - 11*x - 9*x^2). - Zerinvary Lajos, Apr 27 2009

Extensions

G.f. adapted to the offset by Vincenzo Librandi, Nov 22 2012