a(n) = Sum_{k=1..n} Stirling2(n,k) * (k-1)! * phi(k), where phi = A000010.

A330444

a(n) = Sum_{k=1..n} Stirling2(n,k) * (k-1)! * phi(k), where phi = A000010.

Terms

    a(0) =1a(1) =2a(2) =8a(3) =44a(4) =332a(5) =2852a(6) =28268a(7) =330164a(8) =4371452a(9) =62867492a(10) =980090828a(11) =16792404884a(12) =316446118172

External references