a(n) = (2*n)! * [x^(2*n)] (-x/(1 - x))^n/((1 - x)*n!).
A295383
a(n) = (2*n)! * [x^(2*n)] (-x/(1 - x))^n/((1 - x)*n!).
Terms
- a(0) =1a(1) =-4a(2) =72a(3) =-2400a(4) =117600a(5) =-7620480a(6) =614718720a(7) =-59364264960
External references
- oeis: A295383