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

A354138

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

Terms

    a(0) =1a(1) =1a(2) =13a(3) =389a(4) =4357a(5) =1960649a(6) =258805669a(7) =47102631757

External references