A248827 Row sums of A187783 and A089759.

1, 2, 3, 5, 15, 137, 4393, 518625, 239478123, 455196345315, 4054931519864889, 157048983466046778713, 33902817175022723879495899, 33209307490198775518644207834495, 202452250996395056747517509528867065999

Offset

0,2

Links

Tilman Piesk, Table of n, a(n) for n = 0..53

Formula

log(a(n)) ~ n^2 * (log(n/2)/4 + 1/(16*log(n))). - Vaclav Kotesovec, Nov 24 2023

Example

          1                  1
        1   1                2
      1   1   1              3
    1   2   1   1            5
  1   6   6   1   1         15
1  24  90  20   1   1      137

Mathematica

Table[Sum[((n-k)*k)! / (k!)^(n-k), {k, 0, n}], {n, 0, 15}] (* Vaclav Kotesovec, Nov 24 2023 *)

Crossrefs

Sequence in context: A270011 A111183 A330821 * A273525 A377853 A274336

Adjacent sequences: A248824 A248825 A248826 * A248828 A248829 A248830

Keyword

nonn

Author

Tilman Piesk, Oct 28 2014

Status

approved