a(n) = 1 + 3 * Sum_{k=0..n-1} binomial(n,k) * (n-k-1)! * a(k).
A343709
a(n) = 1 + 3 * Sum_{k=0..n-1} binomial(n,k) * (n-k-1)! * a(k).
Terms
- a(0) =1a(1) =4a(2) =28a(3) =295a(4) =4159a(5) =73348a(6) =1552468a(7) =38336569a(8) =1081926157a(9) =34350646636
External references
- oeis: A343709