a(n) = n!^2 * Sum_{k=1..n} Sum_{j=1..k} 1/j^2.
A060944
a(n) = n!^2 * Sum_{k=1..n} Sum_{j=1..k} 1/j^2.
Terms
- a(0) =1a(1) =9a(2) =130a(3) =2900a(4) =93576a(5) =4141872a(6) =241353792a(7) =17929776384
External references
- oeis: A060944
A060944
a(n) = n!^2 * Sum_{k=1..n} Sum_{j=1..k} 1/j^2.