a(n) = (n-1)!*a(n-1)+1.A051399a(n) = (n-1)!*a(n-1)+1.Terms a(0) =0a(1) =1a(2) =2a(3) =5a(4) =31a(5) =745a(6) =89401a(7) =64368721a(8) =324418353841External referencesoeis: A051399