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).

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

Author

Alois P. Heinz, Sep 22 2019

Keywords

• nonn

Examples

			a(4) = 6:
  4 -> 1111
  4 -> 211  -> 1111
  4 -> 31   -> 1111
  4 -> 31   -> 211  -> 1111
  4 -> 22   -> 112  -> 1111
  4 -> 22   -> 211  -> 1111
		

Links

• Wikipedia, Partition (number theory)

Crossrefs

Cf. A002846, A327643, A327697, A327699, A327702.