A081193 a(n) = 6*a(n-1)-8*a(n-2) for n>1, a(0)=1, a(1)=9.

1, 9, 46, 204, 856, 3504, 14176, 57024, 228736, 916224, 3667456, 14674944, 58710016, 234860544, 939483136, 3758014464, 15032221696, 60129214464, 240517513216, 962071363584, 3848288075776, 15393157545984, 61572640669696

Offset: 0

Author

Paul Barry, Mar 11 2003

Keywords

• nonn
• easy

Comments

Third binomial transform of A010687 (period 2: repeat 1,6). [Bruno Berselli, Aug 06 2013]

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• Index entries for linear recurrences with constant coefficients, signature (6,-8).

Programs

Magma

[7*4^n/2-5*2^n/2: n in [0..25]]; // Vincenzo Librandi, Aug 07 2013

Mathematica

CoefficientList[Series[(1 + 3 x)/((1 - 2 x) (1 - 4 x)), {x, 0, 30}], x] (* Vincenzo Librandi, Aug 07 2013 *)

Formula

G.f.: (1+3*x)/((1-2*x)*(1-4*x)).

a(n) = 7*4^n/2-5*2^n/2.