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A127124 Number of endofunctions whose component sizes form the n-th partition in Mathematica order. 1

%I #5 Mar 30 2012 17:35:17

%S 1,1,2,1,4,2,1,9,4,3,2,1,20,9,8,4,3,2,1,51,20,18,9,10,8,4,4,3,2,1,125,

%T 51,40,20,36,18,9,10,12,8,4,4,3,2,1,329,125,102,51,80,40,20,45,36,27,

%U 18,9,20,10,12,8,4,5,4,3,2,1,862,329,250,125,204,102,51,180,80,60,40,20,45

%N Number of endofunctions whose component sizes form the n-th partition in Mathematica order.

%C Can be regarded as a triangle with one row for each size of partition.

%e For n = 3, the 7 endofunctions are (1,2,3) -> (1,1,1), (1,1,2), (1,2,1), (2,1,1), (1,2,3), (1,3,2) and (2,3,1). The components are respectively 123, 123, 13|2, 123, 1|2|3, 1|23 and 123, corresponding to partitions [3], [3], [2,1], [3], [1^3], [2,1] and [3]. The partitions of 3 in Mathematica order are [3], [2,1] and [1^3], so row 3 is 4,2,1.

%e The triangle starts:

%e 1

%e 1

%e 2 1

%e 4 2 1

%e 9 4 3 2 1

%e 20 9 8 4 3 2 1

%K nonn,tabf

%O 0,3

%A _Franklin T. Adams-Watters_, Jan 05 2007

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Last modified April 24 20:08 EDT 2024. Contains 371963 sequences. (Running on oeis4.)