OFFSET
0,2
LINKS
FORMULA
Binomial transform of [1, 1, -1, 3, -1, 3, -1, 3, -1, 3, ...].
For n>0, a(n) = 2 + 2^n - 2*n = 1 + A183155(n-1). - R. J. Mathar, Apr 04 2012
a(n) = 4*a(n-1)-5*a(n-2)+2*a(n-3) for n>3. - Colin Barker, Jun 06 2014
G.f.: -(4*x^3-x^2-2*x+1) / ((x-1)^2*(2*x-1)). - Colin Barker, Jun 06 2014
For n>1, a(n) = A132732(n-1). - Jeppe Stig Nielsen, Dec 29 2017
EXAMPLE
a(4) = 10 = sum of row 4 terms of triangle A132823: (1 + 2 + 4 + 2 + 1).
a(3) = 4 = (1, 3, 3, 1) dot (1, 1, -1, 3) = (1 + 3 -3 + 3).
MAPLE
MATHEMATICA
a[0] = 1; a[n_] := 2 + 2^n - 2*n; Table[a[n], {n, 0, 30}] (* Wesley Ivan Hurt, Jun 06 2014 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Sep 02 2007
STATUS
approved