a(n) = n! * Sum_{k=1..n} H(k)*(n-k)!, where H(k) = Sum_{j=1..k} 1/j.
A109780
a(n) = n! * Sum_{k=1..n} H(k)*(n-k)!, where H(k) = Sum_{j=1..k} 1/j.
Terms
- a(0) =1a(1) =5a(2) =32a(3) =310a(4) =4924a(5) =126648a(6) =4869192a(7) =258608880a(8) =17973530784
External references
- oeis: A109780