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 A299926 a(n) is the number of normal generalized Young tableaux of size n with all rows and columns weakly increasing and all regions skew partitions. 16

%I

%S 1,4,14,60,252,1212,5880,30904,166976,952456,5587840,34217216,

%T 215204960,1401551376,9360467760,64384034784,453328282624,

%U 3274696185568,24173219998912,182546586425408

%N a(n) is the number of normal generalized Young tableaux of size n with all rows and columns weakly increasing and all regions skew partitions.

%C If y is an integer partition of n, 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.

%e The a(3) = 14 tableaux:

%e 1 2 3 1 2 2 1 1 2 1 1 1

%e .

%e 1 3 1 2 1 2 1 2 1 1 1 1

%e 2 3 2 1 2 1

%e .

%e 1 1 1 1

%e 2 2 1 1

%e 3 2 2 1

%t undptns[y_]:=DeleteCases[Select[Tuples[Range[0,#]&/@y],OrderedQ[#,GreaterEqual]&],0,{2}];

%t chn[y_]:=Join[{{{},y}},Join@@Function[c,Append[#,y]&/@chn[c]]/@Take[undptns[y],{2,-2}]];

%t Table[Sum[Length[chn[y]],{y,IntegerPartitions[n]}],{n,8}]

%Y Cf. A000085, A063834, A138178, A153452, A296188, A296561, A297388, A299699, A299925.

%K nonn,more

%O 1,2

%A _Gus Wiseman_, Feb 21 2018

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Last modified February 17 12:32 EST 2020. Contains 331996 sequences. (Running on oeis4.)