a(n) = [x^n] Product_{k=1..n} ((1 + k*x)/(1 - k*x))^2.
A384086
a(n) = [x^n] Product_{k=1..n} ((1 + k*x)/(1 - k*x))^2.
Terms
- a(0) =1a(1) =4a(2) =72a(3) =2352a(4) =112000a(5) =7023540a(6) =546991704a(7) =50923706176
External references
- oeis: A384086
A384086
a(n) = [x^n] Product_{k=1..n} ((1 + k*x)/(1 - k*x))^2.