OFFSET
1,2
COMMENTS
a(n) is a power of 2.
FORMULA
a(n)=Denominator of Sum_{k=0..n^2-1}(Binomial(2k,k)/4^k)-n.
MATHEMATICA
Denominator[Table[Sum[Binomial[2k, k]/4^k, {k, 0, n^2-1}]-n, {n, 1, 10}]]
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Ralf Steiner, Apr 12 2017
STATUS
approved