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

A307318

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

Terms

    a(0) =1a(1) =-2a(2) =37a(3) =-692a(4) =14371a(5) =-315002a(6) =7156969a(7) =-166785320a(8) =3960790687a(9) =-95442311582

External references