A019577 Place n distinguishable balls in n boxes (in n^n ways); let f(n,k) = number of ways that max in any box is k, for 1<=k<=n; sequence gives f(n,2)/n.

0, 1, 6, 45, 420, 4800, 65520, 1045170, 19126800, 395448480, 9120988800, 232248416400, 6471820555200, 195912193276800, 6402199349145600, 224636583525354000, 8423131243022496000, 336138596955120960000, 14224375944427993344000, 636224790017466730080000

Offset

1,3

Links

Alois P. Heinz, Table of n, a(n) for n = 1..200

Formula

Sum n! (n-1)! / ( 2^d (n-2d)! d! d! ), d=1..[ n/2 ].

Crossrefs

Cf. A019576.

Sequence in context: A379942 A291421 A001879 * A097814 A239910 A374844

Adjacent sequences: A019574 A019575 A019576 * A019578 A019579 A019580

Keyword

nonn,easy

Author

Lee Corbin (lcorbin(AT)tsoft.com), N. J. A. Sloane.

Status

approved