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 A215122 Number T(n,k) of solid standard Young tableaux of shape [[(n-k)*k,k],[n-k]]; triangle T(n,k), n>=0, 0<=k<=n, read by rows. 3

%I

%S 1,0,0,0,2,0,0,8,8,0,0,30,174,30,0,0,112,2084,2084,112,0,0,420,21025,

%T 52808,21025,420,0,0,1584,194064,994788,994788,194064,1584,0,0,6006,

%U 1694224,16074586,31497284,16074586,1694224,6006,0

%N Number T(n,k) of solid standard Young tableaux of shape [[(n-k)*k,k],[n-k]]; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

%H Alois P. Heinz, <a href="/A215122/b215122.txt">Rows n = 0..140, flattened</a>

%H S. B. Ekhad, D. Zeilberger, <a href="https://arxiv.org/abs/1202.6229">Computational and Theoretical Challenges on Counting Solid Standard Young Tableaux</a>, arXiv:1202.6229v1 [math.CO], 2012

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a>

%e Triangle T(n,k) begins:

%e 1;

%e 0, 0;

%e 0, 2, 0;

%e 0, 8, 8, 0;

%e 0, 30, 174, 30, 0;

%e 0, 112, 2084, 2084, 112, 0;

%e 0, 420, 21025, 52808, 21025, 420, 0;

%e 0, 1584, 194064, 994788, 994788, 194064, 1584, 0;

%p b:= proc(x, y, z) option remember; `if`(z<y, b(x, z, y),

%p `if`({x, y, z}={0}, 1, `if`(x>y and x>z, b(x-1, y, z), 0)+

%p `if`(y>0, b(x, y-1, z), 0)+ `if`(z>0, b(x, y, z-1), 0)))

%p end:

%p T:= (n, k)-> `if`(k=0 xor k=n, 0, b((n-k)*k, k, n-k)):

%p seq(seq(T(n, k), k=0..n), n=0..10);

%t b[x_, y_, z_] := b[x, y, z] = If[z<y, b[x, z, y], If[Union[{x, y, z}] == {0}, 1, If[x>y && x>z, b[x-1, y, z], 0] + If[y>0, b[x, y-1, z], 0] + If[z>0, b[x, y, z-1], 0]]]; T[n_, k_] := If[k == 0 || k == n, 0, b[(n-k)*k, k, n-k]]; T[0, 0] = 1; Table[Table[T[n, k], {k, 0, n}], {n, 0, 10}] // Flatten (* _Jean-François Alcover_, Jan 19 2015, after _Alois P. Heinz_ *)

%Y Columns k=0-2 give: A000007, A162551(n-1), A215124.

%Y Central elements of rows give A215123.

%K nonn,tabl

%O 0,5

%A _Alois P. Heinz_, Aug 03 2012

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Last modified July 16 23:49 EDT 2019. Contains 325092 sequences. (Running on oeis4.)