OFFSET
0,2
COMMENTS
A007283 = 3*2^n: (3, 6, 12, 24, 48, ...).
LINKS
FORMULA
a(0) = 1, a(1) = 4, a(n) = 3*2^n for n>1.
G.f.: -(1+2*x+4*x^2)/(-1+2*x). - R. J. Mathar, Nov 14 2007
a(n) = 2*a(n-1) for n>1. - Harvey P. Dale, May 31 2017
EXAMPLE
a(3) = 24 = sum of row 3 terms of triangle A132476: (3 + 7 + 13 + 1).
MATHEMATICA
Join[{1, 4}, 3 2^Range[2, 40]] (* or *) Join[{1, 4}, NestList[2#&, 12, 40]] (* Harvey P. Dale, May 31 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Aug 22 2007
STATUS
approved