a(n) is the denominator of Sum_{k=0..n} 1 / (2*k)!.

A354335

a(n) is the denominator of Sum_{k=0..n} 1 / (2*k)!.

Terms

    a(0) =1a(1) =2a(2) =24a(3) =720a(4) =4480a(5) =518400a(6) =479001600a(7) =29059430400

External references