A280882 - OEIS

%I #4 Jan 12 2017 15:04:31

%S 1,10,20,245,56,2100,2640,36795,8140,542542,72436,3311945,6050240,

%T 91668080,2505120,1972220235,92327460,5331136090,6360277000,

%U 320219686633,29187262016,4567704520100,3125812500200,39433339579725,19033980625296,2173716576665550

%N Number of set partitions of [n] into exactly four blocks where sizes of distinct blocks are coprime.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Coprime_integers">Coprime integers</a>

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

%Y Column k=4 of A280880.

%K nonn

%O 4,2

%A _Alois P. Heinz_, Jan 09 2017