OFFSET
0,3
COMMENTS
A generalized Young tableau of shape y is an array obtained by replacing the dots in the Ferrers diagram of y with positive integers. A tableau is normal if its entries span an initial interval of positive integers.
EXAMPLE
The a(4) = 13 tableaux:
1 1 2 2 1 1 1 1
.
1 2 2 1 1 2 1 1 1
1 2 1
.
1 2 1 1 1 1
1 2 2 2 1 1
.
1 2 1 1 1 1
1 2 1
2 2 1
.
1 1
1 1
2 1
2 1
MATHEMATICA
undptns[y_]:=DeleteCases[Select[Tuples[Range[0, #]&/@y], OrderedQ[#, GreaterEqual]&], 0, {2}];
ehn[y_]:=ehn[y]=If[Total[y]=!=1, 1, 0]+Sum[ehn[c], {c, Select[undptns[y], Total[#]>1&&Total[y]-Total[#]>1&]}];
Table[Sum[ehn[y], {y, IntegerPartitions[n]}], {n, 15}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Feb 22 2018
STATUS
approved