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A327699
Number of refinement sequences n -> ... -> {1}^n, where in each step every single part of a nonempty selection of parts is replaced by a partition of itself into two smaller parts (in weakly decreasing order).
4
1, 1, 1, 4, 9, 48, 211, 1736, 9777, 91169, 739174, 8613817, 83763730, 1105436491, 13222076337, 207852246589, 2789691577561, 47759515531854, 755158220565169, 14595210284816038, 255814560447492788, 5373613110108953192, 105867623217924984398, 2460702471446564481641
OFFSET
1,4
EXAMPLE
a(4) = 4:
4 -> 31 -> 211 -> 1111
4 -> 22 -> 1111
4 -> 22 -> 112 -> 1111
4 -> 22 -> 211 -> 1111
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 22 2019
STATUS
approved