A170939 a(n) = 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

0,1

Links

Paolo Xausa, Table of n, a(n) for n = 0..1500

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

Formula

From R. J. Mathar, Feb 15 2010: (Start)

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)). (End)

Mathematica

A170939[n_] := 4^n - 2^n + 2; Array[A170939, 30, 0] (* Paolo Xausa, Mar 09 2026 *)

Crossrefs

Sequence in context: A059687 A204198 A003322 * A030952 A030861 A122972

Adjacent sequences: A170936 A170937 A170938 * A170940 A170941 A170942

Keyword

nonn,easy

Author

N. J. A. Sloane, Feb 13 2010

Status

approved