OFFSET
0,2
LINKS
Stefano Spezia, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: (-1+4*x+2*sqrt(1-4*x))/((1-x)*(1-4*x)). - Ralf Stephan, Apr 03 2004
a(n) = 4*s(n) + 1, with s(n) = A079309(n) = Sum_{k=1..n} C(2k+1, k+1). - Ralf Stephan, Apr 03 2004
MATHEMATICA
CoefficientList[Series[( -1+4x+2*Sqrt[1-4x])/((1-x)(1-4x)), {x, 0, 26}], x] (* Stefano Spezia, May 11 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved