a(1) = 1 and a(n) = Sum_{i=1..n-1} (-1)^i*i*a(i).

A265376

a(1) = 1 and a(n) = Sum_{i=1..n-1} (-1)^i*i*a(i).

Terms

    a(0) =1a(1) =-1a(2) =-3a(3) =6a(4) =30a(5) =-120a(6) =-840a(7) =5040a(8) =45360a(9) =-362880a(10) =-3991680a(11) =39916800a(12) =518918400a(13) =-6227020800a(14) =-93405312000

External references