a(n) = Sum_{k=1..n} (-1)^(n-k)*hypergeom([k, k-2-n], [], 1).

A293295

a(n) = Sum_{k=1..n} (-1)^(n-k)*hypergeom([k, k-2-n], [], 1).

Terms

    a(0) =1a(1) =5a(2) =27a(3) =142a(4) =847a(5) =5817a(6) =45733a(7) =405836a(8) =4012701a(9) =43733965a(10) =520794991a(11) =6726601050a(12) =93651619867

External references