G.f.: Sum_{n>=0} (2*n+x)^n * x^n / (1 + 2*n*x + x^2)^n.
A187746
G.f.: Sum_{n>=0} (2*n+x)^n * x^n / (1 + 2*n*x + x^2)^n.
Terms
- a(0) =1a(1) =2a(2) =13a(3) =100a(4) =984a(5) =11712a(6) =163200a(7) =2603520a(8) =46771200a(9) =934133760a(10) =20530298880a(11) =492355584000
External references
- oeis: A187746