A321730 Number of ways to partition the Young diagram of an integer partition of n into vertical sections of the same sizes as the parts of the original partition.

1, 1, 1, 3, 8, 23, 79, 303, 1294, 5934, 29385, 156232, 884893

Offset: 0

Author

Gus Wiseman, Nov 18 2018

Keywords

• nonn
• more

Comments

A vertical section is a partial Young diagram with at most one square in each row. For example, a suitable partition (shown as a coloring by positive integers) of the Young diagram of (322) is:

1 2 3

1 2

2 3

Examples

			The a(5) = 23 partitions of Young diagrams of integer partitions of 5 into vertical sections of the same sizes as the parts of the original partition, shown as colorings by positive integers:
  1 2 3   1 2 3   1 2 3
  1       2       3
  1       2       3
.
  1 2   1 2   1 2   1 2   1 2   1 2   1 2   1 2   1 2   1 2
  1 2   1 3   1 3   2 1   3 1   3 1   2 3   3 2   2 3   3 2
  3     2     3     3     2     3     1     1     3     3
.
  1 2   1 2   1 2   1 2   1 2   1 2   1 2   1 2   1 2
  1     3     3     2     3     3     3     3     3
  3     1     4     3     2     4     3     4     4
  4     4     1     4     4     2     4     3     4
.
  1
  2
  3
  4
  5
		

Crossrefs

Cf. A000110, A000258, A000700, A000701, A006052, A007016, A008277, A321728, A321729, A321731, A321737, A321738.

Programs

Mathematica

spsu[,{}]:={{}};spsu[foo,set:{i_,_}]:=Join@@Function[s,Prepend[#,s]&/@spsu[Select[foo,Complement[#,Complement[set,s]]=={}&],Complement[set,s]]]/@Cases[foo,{i,_}];
ptnpos[y_]:=Position[Table[1,{#}]&/@y,1];
ptnverts[y_]:=Select[Join@@Table[Subsets[ptnpos[y],{k}],{k,Reverse[Union[y]]}],UnsameQ@@First/@#&];
Table[Sum[Length[Select[spsu[ptnverts[y],ptnpos[y]],Function[p,Sort[Length/@p]==Sort[y]]]],{y,IntegerPartitions[n]}],{n,5}]