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Number of set partitions of [n] such that i-j is a multiple of five for all i,j belonging to the same block.
2

%I #6 Jul 15 2016 16:54:07

%S 1,1,1,1,1,1,2,4,8,16,32,80,200,500,1250,3125,9375,28125,84375,253125,

%T 759375,2632500,9126000,31636800,109674240,380204032,1484258048,

%U 5794315072,22620114608,88305447412,344730881243,1489305334237,6434092503083,27796547414797

%N Number of set partitions of [n] such that i-j is a multiple of five for all i,j belonging to the same block.

%H Alois P. Heinz, <a href="/A275072/b275072.txt">Table of n, a(n) for n = 0..772</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Partition_of_a_set">Partition of a set</a>

%F a(n) = Product_{i=0..4} A000110(floor((n+i)/5)).

%e a(9) = 16: 16|27|38|49|5, 16|27|38|4|5|9, 16|27|3|49|5|8, 16|27|3|4|5|8|9, 16|2|38|49|5|7, 16|2|38|4|5|7|9, 16|2|3|49|5|7|8, 16|2|3|4|5|7|8|9, 1|27|38|49|5|6, 1|27|38|4|5|6|9, 1|27|3|49|5|6|8, 1|27|3|4|5|6|8|9, 1|2|38|49|5|6|7, 1|2|38|4|5|6|7|9, 1|2|3|49|5|6|7|8, 1|2|3|4|5|6|7|8|9.

%Y Column k=5 of A275069.

%Y Cf. A000110.

%K nonn

%O 0,7

%A _Alois P. Heinz_, Jul 15 2016