a(n) = Sum_{k=1..n} binomial(n,k) * gcd(n,k) * a(k-1), with a(0) = 1.
A159666
a(n) = Sum_{k=1..n} binomial(n,k) * gcd(n,k) * a(k-1), with a(0) = 1.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =18a(4) =104a(5) =665a(6) =5430a(7) =45647a(8) =457008a(9) =4903380a(10) =58782190a(11) =735362309a(12) =10577094600a(13) =153445432699
External references
- oeis: A159666