a(n) = binomial((n+1)*(2*n+1), n) / ((n+1)*(2*n+1)).
A299429
a(n) = binomial((n+1)*(2*n+1), n) / ((n+1)*(2*n+1)).
Terms
- a(0) =1a(1) =1a(2) =7a(3) =117a(4) =3311a(5) =135408a(6) =7324878a(7) =495729741a(8) =40411916335
External references
- oeis: A299429