a(n) = n! * Sum_{k=0..floor(n/5)} (-n/120)^k /(k! * (n-5*k)!).

A362346

a(n) = n! * Sum_{k=0..floor(n/5)} (-n/120)^k /(k! * (n-5*k)!).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =-4a(6) =-35a(7) =-146a(8) =-447a(9) =-1133a(10) =10081a(11) =162625a(12) =1188001a(13) =6073354a(14) =24692669a(15) =-340585244a(16) =-8007557375a(17) =-83565282891a(18) =-598436312543

External references