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A327698
Number of refinement sequences n -> ... -> {1}^n, where in each step exactly one part is replaced by a partition of itself into smaller parts (in weakly decreasing order).
4
1, 1, 2, 6, 17, 74, 300, 1755, 9360, 65510, 442117, 3802889, 30213386, 294892947, 2789021105, 31360525517, 334374848070, 4184958056248, 50606351991305, 704124800141153, 9452367941048830, 143309007303310536, 2124982437997726705, 35389562541842450218
OFFSET
1,3
EXAMPLE
a(4) = 6:
4 -> 1111
4 -> 211 -> 1111
4 -> 31 -> 1111
4 -> 31 -> 211 -> 1111
4 -> 22 -> 112 -> 1111
4 -> 22 -> 211 -> 1111
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 22 2019
STATUS
approved