A030851 a(n) = floor(exp(1/21) * n!).

1, 2, 6, 25, 125, 755, 5285, 42286, 380578, 3805780, 41863584, 502363009, 6530719126, 91430067771, 1371451016567, 21943216265073, 373034676506249, 6714624177112491, 127577859365137340, 2551557187302746813

Offset: 1

Author

Simon Plouffe

Keywords

• nonn
• easy

Crossrefs

Cf. A021025 (1/21).

Programs

Mathematica

Floor[Exp[1/21] Range[20]!] (* Harvey P. Dale, Jan 22 2015 *)