a(n) = (n!)^2 * Sum_{k=1..n} 1/(k^2*(k-1)!).
A061572
a(n) = (n!)^2 * Sum_{k=1..n} 1/(k^2*(k-1)!).
Terms
- a(0) =1a(1) =5a(2) =47a(3) =758a(4) =18974a(5) =683184a(6) =33476736a(7) =2142516144a(8) =173543847984
External references
- oeis: A061572
A061572
a(n) = (n!)^2 * Sum_{k=1..n} 1/(k^2*(k-1)!).