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Number of ordered set partitions of [n] with nondecreasing block sizes and maximal block size equal to six.
2

%I #4 May 01 2016 17:41:48

%S 1,7,84,840,9870,113652,1480248,19699680,286768482,4358914560,

%T 71096721696,1216711960464,22116370171896,421629228820800,

%U 8473857766133760,178260053918650704,3931319749640138856,90499126549555707984,2174651142277047610176,54390059451824183287200

%N Number of ordered set partitions of [n] with nondecreasing block sizes and maximal block size equal to six.

%H Alois P. Heinz, <a href="/A272496/b272496.txt">Table of n, a(n) for n = 6..450</a>

%F E.g.f.: x^6 * Product_{i=1..6} (i-1)!/(i!-x^i).

%p b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,

%p b(n, i-1)+`if`(i>n, 0, binomial(n, i)*b(n-i, i))))

%p end:

%p a:= n-> (k-> b(n, k) -b(n, k-1))(6):

%p seq(a(n), n=6..30);

%Y Column k=6 of A262071.

%K nonn

%O 6,2

%A _Alois P. Heinz_, May 01 2016