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A327697 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 smaller parts (in weakly decreasing order). 4
1, 1, 2, 7, 22, 122, 598, 4683, 31148, 292008, 2560274, 30122014, 313694962, 4189079688, 53048837390, 826150653479, 11827659365138, 204993767192252, 3371451881544534, 65337695492942258, 1198123466804343518, 25318312971995895392, 516420623159289735874 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..23.

Wikipedia, Partition (number theory)

EXAMPLE

a(1) = 1:

  1

a(2) = 1:

  2 -> 11

a(3) = 2:

  3 -> 111

  3 -> 21   -> 111

a(4) = 7:

  4 -> 1111

  4 -> 211  -> 1111

  4 -> 31   -> 1111

  4 -> 31   -> 211  -> 1111

  4 -> 22   -> 1111

  4 -> 22   -> 112  -> 1111

  4 -> 22   -> 211  -> 1111

CROSSREFS

Cf. A002846, A327643, A327698, A327699, A327702.

Sequence in context: A217138 A004300 A049369 * A308548 A153523 A153551

Adjacent sequences:  A327694 A327695 A327696 * A327698 A327699 A327700

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 22 2019

STATUS

approved

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Last modified February 20 14:03 EST 2020. Contains 332078 sequences. (Running on oeis4.)