A019577 - OEIS

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.

%I #9 Jul 29 2014 16:08:32

%S 0,1,6,45,420,4800,65520,1045170,19126800,395448480,9120988800,

%T 232248416400,6471820555200,195912193276800,6402199349145600,

%U 224636583525354000,8423131243022496000,336138596955120960000,14224375944427993344000,636224790017466730080000

%N 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.

%H Alois P. Heinz, <a href="/A019577/b019577.txt">Table of n, a(n) for n = 1..200</a>

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

%Y Cf. A019576.

%K nonn,easy

%O 1,3

%A Lee Corbin (lcorbin(AT)tsoft.com), _N. J. A. Sloane_.