A112369 a(n) = -1 + Sum_{i=0..n} 2^i*i!.

0, 2, 10, 58, 442, 4282, 50362, 695482, 11017402, 196811962, 3912703162, 85662309562, 2047652863162, 53059407256762, 1481388530277562, 44331262220901562, 1415527220320869562, 48036189795719781562, 1726380042510080613562, 65503446445655792229562, 2616586102571484256869562

Offset: 0

Author

N. J. A. Sloane, Dec 02 2005

Keywords

• nonn

Crossrefs

Cf. A004400, A112368.

Programs

Mathematica

s = 0; lst = {s}; Do[s += n!!; AppendTo[lst, s], {n, 2, 38, 2}]; lst (* Zerinvary Lajos, Jul 13 2009 *)
Join[{0},Accumulate[Table[2^x x!,{x,20}]]] (* Harvey P. Dale, Apr 01 2018 *)