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An alternating sum of decreasing powers.
6

%I #12 Jun 13 2015 00:51:02

%S 1,3,11,45,191,813,3431,14325,59231,242973,990551,4019205,16249871,

%T 65522733,263668871,1059425685,4251986111,17050860093,68332318391,

%U 273716169765,1096025891951,4387588255053,17560809179111,70274609387445

%N An alternating sum of decreasing powers.

%C Binomial transform of A083323.

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9,-26,24).

%F a(n) = 4^n - 3^n + 2^n

%F G.f.: (1-6*x+10*x^2)/((1-2*x)*(1-3*x)*(1-4*x))

%F E.g.f.: exp(4*x) - exp(3*x) + exp(2*x)

%F a(n) = 9*a(n-1) - 26*a(n-2) + 24*a(n-3). - _Geoffrey Critzer_, Dec 01 2013

%t Table[4^n-3^n+2^n,{n,0,23}] (* _Geoffrey Critzer_, Dec 01 2013 *)

%Y Equals 2 * A053154(n) + 1.

%K easy,nonn

%O 0,2

%A _Paul Barry_, Apr 27 2003