OFFSET
0,2
FORMULA
a(n) ~ phi^(4*n + 1) / sqrt(5), where phi = A001622 = (1 + sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Apr 12 2018
MATHEMATICA
Table[Sum[Binomial[2n+i, 2i], {i, 0, n}], {n, 0, 20}] (* Harvey P. Dale, Apr 12 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Ralf Stephan, Jun 03 2005
STATUS
approved