A174993 a(n) = -Floor[n/2]! + Sum[(Eulerian[n - j, j]), {j, 0, Floor[n/2]}].

0, 0, 1, 4, 11, 36, 119, 443, 1718, 7245, 32313, 153730, 771677, 4088053, 22741818, 132596893, 807840501, 5132194862, 33924901021, 232905225561, 1657803862422, 12215420390037, 93042805475305, 731622623516178, 5931914758691917, 49535825763153373, 425606813712984146, 3758735172560999933, 34089943206777076429, 317245175458777517030

Offset: 1

Author

Roger L. Bagula, Dec 02 2010

Keywords

• nonn

Crossrefs

Cf. A000800.

Programs

Mathematica

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Formula

a(n)=-Floor[n/2]! + Sum[(Eulerian[n - j, j]), {j, 0, Floor[n/2]}]=A000800(n)-Floor[(n-1)/2]!