OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2,0,-1)
FORMULA
From R. J. Mathar, Apr 07 2011: (Start)
G.f.: (1+5*x-5*x^2)/((1-x)*(1-x-x^2)).
a(n) = 2*A000285(n) - 1. (End)
a(n) = 2*F(n+2) + 4*F(n) - 1, where F = A000045. - G. C. Greubel, Aug 25 2017
MATHEMATICA
a[0]=1; a[1]=7; a[n_]:=a[n]=a[n-1]+a[n-2]+1; Table[a[n], {n, 0, 40}] (* Harvey P. Dale, Jan 23 2011 *)
PROG
(PARI) x='x+O('x^50); Vec((1+5*x-5*x^2)/((1-x)*(1-x-x^2))) \\ G. C. Greubel, Aug 25 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved