a(n) = (n!)^2 * (1 + Sum_{k=0..n-1} 1/((k+1)(k!)^2)).
A026025
a(n) = (n!)^2 * (1 + Sum_{k=0..n-1} 1/((k+1)(k!)^2)).
Terms
- a(0) =1a(1) =2a(2) =10a(3) =93a(4) =1492a(5) =37305a(6) =1342986a(7) =65806321a(8) =4211604552a(9) =341139968721
External references
- oeis: A026025