a(n) = (n!)^2 * Sum_{k=0..n-1} 1 / ((n-k) * k!)^2.
A346410
a(n) = (n!)^2 * Sum_{k=0..n-1} 1 / ((n-k) * k!)^2.
Terms
- a(0) =0a(1) =1a(2) =5a(3) =22a(4) =152a(5) =2001a(6) =45097a(7) =1527506a(8) =71864928a(9) =4466430513a(10) =353828600029
External references
- oeis: A346410