A131107 - OEIS

A131107

Rectangular array read by antidiagonals: k objects are each put into one of n boxes, independently with equal probability. a(n, k) is the expected number of boxes with exactly one object (n, k >= 1). Sequence gives the denominators.

%I #2 Mar 30 2012 17:38:08

%S 1,1,1,1,1,1,1,3,4,1,1,2,3,2,1,1,5,16,27,16,1,1,3,25,16,81,16,1,1,7,

%T 12,125,256,81,64,1,1,4,49,54,125,512,729,16,1,1,9,64,343,1296,3125,

%U 4096,2187,256,1,1,5,27,128,2401,1296,15625,2048,729,256,1,1,11,100,729,4096

%N Rectangular array read by antidiagonals: k objects are each put into one of n boxes, independently with equal probability. a(n, k) is the expected number of boxes with exactly one object (n, k >= 1). Sequence gives the denominators.

%Y Cf. A131106 gives the numerators.

%K easy,frac,nonn,tabl

%O 1,8

%A _David Wasserman_, Jun 15 2007