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Number of ordered set partitions of {1,2,...,n} such that no part has the same size as any of its six immediate predecessors.
2

%I #5 May 01 2016 17:20:27

%S 1,1,1,7,9,31,403,757,2873,12607,333051,761377,3699435,16383121,

%T 108710085,4855474267,13594184793,76375572751,388660153867,

%U 2504206435681,20148774553859,1556349601444477,5050276538344665,33326552998257031,186169293932977115,1305062351972825281,9600936552132048553,106019265737746665727,12708226588208611056333,98137877588880676995127

%N Number of ordered set partitions of {1,2,...,n} such that no part has the same size as any of its six immediate predecessors.

%H Alois P. Heinz, <a href="/A272434/b272434.txt">Table of n, a(n) for n = 0..50</a>

%Y Column k=6 of A261959.

%K nonn

%O 0,4

%A _Alois P. Heinz_, Apr 29 2016