A121050 Partial sums of floor(n!/e^n).

0, 0, 0, 0, 0, 1, 5, 18, 62, 226, 892, 3835, 17910, 90401, 490421, 2844970, 17570207, 115078228, 796630963, 5811215750, 44551231383, 358087648032, 3010990488143, 26433752431402, 241852566790848, 2302304545944415, 22768248457537798, 233580248716343376

Offset: 1

Author

Jonathan Vos Post, Aug 08 2006

Keywords

• easy
• nonn

Crossrefs

Cf. A000142, A055775.

Programs

Mathematica

Accumulate[Table[Floor[n!/Exp[n]],{n,30}]] (* Harvey P. Dale, Aug 25 2016 *)

Formula

a(n) = Sum_{i=1..n} floor(i!/exp(i)).

Extensions

Corrected by and incorrect examples removed by Harvey P. Dale, Aug 25 2016