A153981 a(n) = 36*Fibonacci(2*n+1) - 4.

32, 68, 176, 464, 1220, 3200, 8384, 21956, 57488, 150512, 394052, 1031648, 2700896, 7071044, 18512240, 48465680, 126884804, 332188736, 869681408, 2276855492, 5960885072, 15605799728, 40856514116, 106963742624, 280034713760, 733140398660

Offset: 0

Author

Paul Curtz, Jan 04 2009

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• Index entries for linear recurrences with constant coefficients, signature (4, -4, 1).

Programs

Magma

[36*Fibonacci(2*n+1)-4: n in [0..30]]; // Vincenzo Librandi, Aug 07 2011

Mathematica

36*Fibonacci[2*Range[0,30]+1]-4 (* or *) LinearRecurrence[{4,-4,1},{32,68,176},30] (* Harvey P. Dale, Jan 26 2013 *)

Formula

a(n) = 4*A153873(n) = 2*A153819(n).

a(n) = 5 (mod 9) = A010716(n) (mod 9).

a(n) = 3*a(n-1) - a(n-2) + 4.

a(n) = 4*a(n-1) - 4*a(n-2) + a(n-3).

a(n) = 3*a(n-1) - 3*a(n-3) + a(n-4).

G.f.: 4*(8 - 15*x + 8x^2)/((1-x)*(1 -3*x +x^2)). - R. J. Mathar, Jan 23 2009

Extensions

Edited and extended by R. J. Mathar and N. J. A. Sloane, Jan 23 2009