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

A335090

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

Terms

    a(0) =0a(1) =1a(2) =34a(3) =1891a(4) =164196a(5) =20760741a(6) =3616621254a(7) =832001250375

External references