A083085 a(n) = (2+(-5)^n)/3.
1, -1, 9, -41, 209, -1041, 5209, -26041, 130209, -651041, 3255209, -16276041, 81380209, -406901041, 2034505209, -10172526041, 50862630209, -254313151041, 1271565755209, -6357828776041, 31789143880209, -158945719401041, 794728597005209, -3973642985026041
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..300
- Index entries for linear recurrences with constant coefficients, signature (-4,5).
Crossrefs
Cf. A083086.
Programs
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Magma
[(2+(-5)^n)/3: n in [0..30]]; // Vincenzo Librandi, Nov 12 2011
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Maple
A083085:=n->(2+(-5)^n)/3: seq(A083085(n), n=0..30); # Wesley Ivan Hurt, Nov 02 2014
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Mathematica
Table[(2 + (-5)^n)/3, {n, 0, 30}] (* Wesley Ivan Hurt, Nov 02 2014 *)
Formula
a(n) = (2+(-5)^n)/3.
G.f.: (1+3*x)/((1+5*x)*(1-x)).
E.g.f.: (2*exp(x)+exp(-5*x))/3.
a(n) = -5*a(n-1) + 4. - Vincenzo Librandi, Nov 12 2011
Comments