A327699 - OEIS

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).

1, 1, 1, 4, 9, 48, 211, 1736, 9777, 91169, 739174, 8613817, 83763730, 1105436491, 13222076337, 207852246589, 2789691577561, 47759515531854, 755158220565169, 14595210284816038, 255814560447492788, 5373613110108953192, 105867623217924984398, 2460702471446564481641

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OFFSET

1,4

LINKS

Table of n, a(n) for n=1..24.

Wikipedia, Partition (number theory)

EXAMPLE

a(4) = 4:

4 -> 31 -> 211 -> 1111

4 -> 22 -> 1111

4 -> 22 -> 112 -> 1111

4 -> 22 -> 211 -> 1111