A015562 Expansion of x/(1 - 7*x - 5*x^2).

0, 1, 7, 54, 413, 3161, 24192, 185149, 1417003, 10844766, 82998377, 635212469, 4861479168, 37206416521, 284752311487, 2179298263014, 16678849398533, 127648437104801, 976933306726272, 7476775332607909, 57222093861886723

Offset: 0

Author

Olivier Gérard

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (7,5).

Programs

Magma

[n le 2 select n-1 else 7*Self(n-1) + 5*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Nov 14 2012

Mathematica

Join[{a=0,b=1},Table[c=7*b+5*a;a=b;b=c,{n,100}]] (* Vladimir Joseph Stephan Orlovsky, Jan 17 2011 *)
LinearRecurrence[{7, 5}, {0, 1}, 30] (* Vincenzo Librandi, Nov 14 2012 *)

PARI

x='x+O('x^30); concat([0], Vec(x/(1-7*x-5*x^2))) \\ G. C. Greubel, Dec 30 2017

Sage

[lucas_number1(n,7,-5) for n in range(0, 21)] # Zerinvary Lajos, Apr 24 2009

Formula

a(n) = 7*a(n-1) + 5*a(n-2).