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A280882
Number of set partitions of [n] into exactly four blocks where sizes of distinct blocks are coprime.
1
1, 10, 20, 245, 56, 2100, 2640, 36795, 8140, 542542, 72436, 3311945, 6050240, 91668080, 2505120, 1972220235, 92327460, 5331136090, 6360277000, 320219686633, 29187262016, 4567704520100, 3125812500200, 39433339579725, 19033980625296, 2173716576665550
OFFSET
4,2
CROSSREFS
Column k=4 of A280880.
Sequence in context: A217318 A239237 A018990 * A335802 A319599 A160479
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jan 09 2017
STATUS
approved