a(n) = (n!)^n * Sum_{k=0..n} 1 / ((k!)^n * (n-k)!).

A336249

a(n) = (n!)^n * Sum_{k=0..n} 1 / ((k!)^n * (n-k)!).

Terms

    a(0) =1a(1) =2a(2) =7a(3) =172a(4) =79745a(5) =1375363126

External references