A170939 - OEIS

%I #20 Mar 09 2026 09:51:22

%S 2,4,14,58,242,994,4034,16258,65282,261634,1047554,4192258,16773122,

%T 67100674,268419074,1073709058,4294901762,17179738114,68719214594,

%U 274877382658,1099510579202,4398044413954,17592181850114,70368735789058,281474959933442,1125899873288194

%N a(n) = 4^n - 2^n + 2.

%H Paolo Xausa, <a href="/A170939/b170939.txt">Table of n, a(n) for n = 0..1500</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8).

%F From _R. J. Mathar_, Feb 15 2010: (Start)

%F a(n) = 7*a(n-1) -14*a(n-2) +8*a(n-3) = 2*A134169(n).

%F G.f.: 2*(1-5*x+7*x^2)/((1-x) * (2*x-1) * (4*x-1)). (End)

%t A170939[n_] := 4^n - 2^n + 2; Array[A170939, 30, 0] (* _Paolo Xausa_, Mar 09 2026 *)

%K nonn,easy

%O 0,1

%A _N. J. A. Sloane_, Feb 13 2010