a(n) = (1/2^n)* Sum_{k=0..n} binomial(n,k)*(n+k)^(n-1).
A138903
a(n) = (1/2^n)* Sum_{k=0..n} binomial(n,k)*(n+k)^(n-1).
Terms
- a(0) =1a(1) =3a(2) =21a(3) =234a(4) =3590a(5) =70254a(6) =1672972a(7) =46955760a(8) =1517994792a(9) =55549351800
External references
- oeis: A138903