G.f.: 1 = Sum_{n>=0} a(n)*x^n * Sum_{k=0..n+1} C(n+1,k)^2*(-x)^k.
A180716
G.f.: 1 = Sum_{n>=0} a(n)*x^n * Sum_{k=0..n+1} C(n+1,k)^2*(-x)^k.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =35a(4) =524a(5) =11844a(6) =374544a(7) =15740121a(8) =846918340a(9) =56716282700
External references
- oeis: A180716