A170939 4^n-2^n+2.

2, 4, 14, 58, 242, 994, 4034, 16258, 65282, 261634, 1047554, 4192258, 16773122, 67100674, 268419074, 1073709058, 4294901762, 17179738114, 68719214594, 274877382658, 1099510579202, 4398044413954, 17592181850114, 70368735789058, 281474959933442, 1125899873288194

Offset: 0

Author

N. J. A. Sloane, Feb 13 2010

Keywords

• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (7, -14, 8).

Formula

a(n)= 7*a(n-1) -14*a(n-2) +8*a(n-3) = 2*A134169(n). G.f.: 2*(1-5*x+7*x^2)/((1-x) * (2*x-1) * (4*x-1)). [From R. J. Mathar, Feb 15 2010]