a(n) = (2*n+1)!*Sum_{k=0..n} (-1)^k/(2*k+1)!.

A074790

a(n) = (2*n+1)!*Sum_{k=0..n} (-1)^k/(2*k+1)!.

Terms

    a(0) =1a(1) =5a(2) =101a(3) =4241a(4) =305353a(5) =33588829a(6) =5239857325

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