OFFSET
1,2
LINKS
FORMULA
a(n) = 2 + 2^(n+1) for n >= 2; a(1)=1. - Emeric Deutsch, Oct 24 2007
O.g.f.: (-1-3*x+6*x^2)/((1-x)*(-1+2*x)). - R. J. Mathar, Apr 02 2008
EXAMPLE
a(4) = 18 = (1, 3, 3, 1) dot (1, 5, -1, 5) = (1 + 15 - 3 + 5).
MAPLE
1, seq(2^(n+1)+2, n=1..25); # Emeric Deutsch, Oct 24 2007
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Oct 21 2007
EXTENSIONS
More terms from Emeric Deutsch, Oct 24 2007
More terms from R. J. Mathar, Apr 02 2008
STATUS
approved