a(n) = C(2*2^n + 2*n, n)*2^n/(2^n + n); a(n) = coefficient of x^n in Catalan(x)^(2*2^n).
A136552
a(n) = C(2*2^n + 2*n, n)*2^n/(2^n + n); a(n) = coefficient of x^n in Catalan(x)^(2*2^n).
Terms
- a(0) =1a(1) =4a(2) =44a(3) =1120a(4) =73112a(5) =13931904a(6) =8577576576
External references
- oeis: A136552