a(n) = ((2*n+1)!!)^n * (Sum_{k=1..n} 1/(2*k+1)^n).

A335096

a(n) = ((2*n+1)!!)^n * (Sum_{k=1..n} 1/(2*k+1)^n).

Terms

    a(0) =0a(1) =1a(2) =34a(3) =55511a(4) =11575291716

External references