A165813 a(n) = n*(a(n-1)+3), a(0)=1.

1, 4, 14, 51, 216, 1095, 6588, 46137, 369120, 3322107, 33221100, 365432133, 4385185632, 57007413255, 798103785612, 11971556784225, 191544908547648, 3256263445310067, 58612742015581260, 1113642098296043997

Offset: 0

Author

Philippe Deléham, Sep 28 2009

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..250

Crossrefs

Cf. A000142, A033540, A165792.

Programs

Mathematica

FoldList[#1*#2 + 3 #2 &, 1, Range[19]] (* Robert G. Wilson v, Jul 07 2012 *)

Formula

a(n) = n! + 3*floor(e*n!) - 3. - Gary Detlefs, Jun 06 2010