a(n) = |Sum_{k=0..n} (-1)^k*(3k)!!|.

A290046

a(n) = |Sum_{k=0..n} (-1)^k*(3k)!!|.

Terms

    a(0) =1a(1) =2a(2) =46a(3) =899a(4) =45181a(5) =1981844a(6) =183812716a(7) =13565497859

External references