a(1) = 1; for n>1, a(n) = n*a(n-1) + 1 if n is a prime else a(n) = n*a(n-1) - 1.

A093463

a(1) = 1; for n>1, a(n) = n*a(n-1) + 1 if n is a prime else a(n) = n*a(n-1) - 1.