OFFSET
1,2
COMMENTS
FORMULA
a(n) = denominator(r(n)), n >= 1.
MATHEMATICA
Accumulate[Table[2 1/Binomial[2n, n], {n, 30}]]//Denominator (* Harvey P. Dale, Aug 12 2022 *)
PROG
(PARI) a(n) = denominator(2*sum(k=1, n, 1/binomial(2*k, k))); \\ Michel Marcus, Nov 09 2019
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
Wolfdieter Lang, Jul 13 2007
EXTENSIONS
More terms from Michel Marcus, Nov 09 2019
STATUS
approved