cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A182172 Number A(n,k) of standard Young tableaux of n cells and height <= k; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 2, 1, 0, 1, 1, 2, 3, 1, 0, 1, 1, 2, 4, 6, 1, 0, 1, 1, 2, 4, 9, 10, 1, 0, 1, 1, 2, 4, 10, 21, 20, 1, 0, 1, 1, 2, 4, 10, 25, 51, 35, 1, 0, 1, 1, 2, 4, 10, 26, 70, 127, 70, 1, 0, 1, 1, 2, 4, 10, 26, 75, 196, 323, 126, 1, 0, 1, 1, 2, 4, 10, 26, 76, 225, 588, 835, 252, 1, 0
Offset: 0

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Author

Alois P. Heinz, Apr 16 2012

Keywords

Comments

Also the number A(n,k) of standard Young tableaux of n cells and <= k columns.
A(n,k) is also the number of n-length words w over a k-ary alphabet {a1,a2,...,ak} such that for every prefix z of w we have #(z,a1) >= #(z,a2) >= ... >= #(z,ak), where #(z,x) counts the letters x in word z. The A(4,4) = 10 words of length 4 over alphabet {a,b,c,d} are: aaaa, aaab, aaba, abaa, aabb, abab, aabc, abac, abca, abcd.

Examples

			A(4,2) = 6, there are 6 standard Young tableaux of 4 cells and height <= 2:
  +------+  +------+  +---------+  +---------+  +---------+  +------------+
  | 1  3 |  | 1  2 |  | 1  3  4 |  | 1  2  4 |  | 1  2  3 |  | 1  2  3  4 |
  | 2  4 |  | 3  4 |  | 2 .-----+  | 3 .-----+  | 4 .-----+  +------------+
  +------+  +------+  +---+        +---+        +---+
Square array A(n,k) begins:
  1,  1,  1,   1,   1,   1,   1,   1,   1, ...
  0,  1,  1,   1,   1,   1,   1,   1,   1, ...
  0,  1,  2,   2,   2,   2,   2,   2,   2, ...
  0,  1,  3,   4,   4,   4,   4,   4,   4, ...
  0,  1,  6,   9,  10,  10,  10,  10,  10, ...
  0,  1, 10,  21,  25,  26,  26,  26,  26, ...
  0,  1, 20,  51,  70,  75,  76,  76,  76, ...
  0,  1, 35, 127, 196, 225, 231, 232, 232, ...
  0,  1, 70, 323, 588, 715, 756, 763, 764, ...
		

Crossrefs

Main diagonal gives A000085.
A(2n,n) gives A293128.

Programs

  • Maple
    h:= proc(l) local n; n:=nops(l); add(i, i=l)! /mul(mul(1+l[i]-j
           +add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n)
        end:
    g:= proc(n, i, l) option remember;
          `if`(n=0, h(l), `if`(i<1, 0, `if`(i=1, h([l[], 1$n]),
            g(n, i-1, l) +`if`(i>n, 0, g(n-i, i, [l[], i])))))
        end:
    A:= (n, k)-> g(n, k, []):
    seq(seq(A(n, d-n), n=0..d), d=0..15);
  • Mathematica
    h[l_List] := Module[{n = Length[l]}, Sum[i, {i, l}]!/Product[Product[1 + l[[i]] - j + Sum[If[l[[k]] >= j, 1, 0], {k, i+1, n}], {j, 1, l[[i]]}], {i, 1, n}]];
    g[n_, i_, l_List] := g[n, i, l] = If[n == 0, h[l], If[i < 1, 0, If[i == 1, h[Join[l, Array[1&, n]]], g [n, i-1, l] + If[i > n, 0, g[n-i, i, Append[l, i]]]]]];
    a[n_, k_] := g[n, k, {}];
    Table[Table[a[n, d-n], {n, 0, d}], {d, 0, 15}] // Flatten (* Jean-François Alcover, Dec 06 2013, translated from Maple *)

Formula

Conjecture: A(n,k) ~ k^n/Pi^(k/2) * (k/n)^(k*(k-1)/4) * Product_{j=1..k} Gamma(j/2). - Vaclav Kotesovec, Sep 12 2013

A047884 Triangle of numbers a(n,k) = number of Young tableaux with n cells and k rows (1 <= k <= n); also number of self-inverse permutations on n letters in which the length of the longest scattered (i.e., not necessarily contiguous) increasing subsequence is k.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 3, 1, 1, 9, 11, 4, 1, 1, 19, 31, 19, 5, 1, 1, 34, 92, 69, 29, 6, 1, 1, 69, 253, 265, 127, 41, 7, 1, 1, 125, 709, 929, 583, 209, 55, 8, 1, 1, 251, 1936, 3356, 2446, 1106, 319, 71, 9, 1, 1, 461, 5336, 11626, 10484, 5323, 1904, 461, 89, 10, 1
Offset: 1

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Author

Keywords

Examples

			For n=3 the 4 tableaux are
  1 2 3 . 1 2 . 1 3 . 1
  . . . . 3 . . 2 . . 2
  . . . . . . . . . . 3
Triangle begins:
  1;
  1,   1;
  1,   2,    1;
  1,   5,    3,     1;
  1,   9,   11,     4,     1;
  1,  19,   31,    19,     5,    1;
  1,  34,   92,    69,    29,    6,    1;
  1,  69,  253,   265,   127,   41,    7,   1;
  1, 125,  709,   929,   583,  209,   55,   8,  1;
  1, 251, 1936,  3356,  2446, 1106,  319,  71,  9,  1;
  1, 461, 5336, 11626, 10484, 5323, 1904, 461, 89, 10,  1;
  ...
		

References

  • W. Fulton, Young Tableaux, Cambridge, 1997.
  • D. Stanton and D. White, Constructive Combinatorics, Springer, 1986.

Crossrefs

Row sums give A000085.
Cf. A049400, A049401, and A178249 which imposes contiguity.
Columns k=1-10 give: A000012, A014495, A217323, A217324, A217325, A217326, A217327, A217328, A217321, A217322. - Alois P. Heinz, Oct 03 2012
a(2n,n) gives A267436.

Programs

  • Maple
    h:= proc(l) local n; n:=nops(l); add(i, i=l)!/mul(mul(1+l[i]-j+
           add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n)
        end:
    g:= proc(n, i, l) `if`(n=0 or i=1, (p->h(p)*x^`if`(p=[], 0, p[1]))
          ([l[], 1$n]), add(g(n-i*j, i-1, [l[], i$j]), j=0..n/i))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=1..n))(g(n$2, [])):
    seq(T(n), n=1..14); # Alois P. Heinz, Apr 16 2012, revised Mar 05 2014
  • Mathematica
    Table[ Plus@@( NumberOfTableaux/@ Reverse/@Union[ Sort/@(Compositions[ n-m, m ]+1) ]), {n, 12}, {m, n} ]
    (* Second program: *)
    h[l_] := With[{n=Length[l]}, Total[l]!/Product[Product[1+l[[i]]-j+Sum[If[ l[[k]] >= j, 1, 0], {k, i+1, n}], {j, 1, l[[i]]}], {i, 1, n}]];
    g[n_, i_, l_] := If[n== 0|| i==1, Function[p, h[p]*x^If[p == {}, 0, p[[1]] ] ] [ Join[l, Array[1&, n]]], Sum[g[n-i*j, i-1, Join[l, Array[i&, j]]], {j, 0, n/i}]];
    T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 1, n}]][g[n, n, {}]];
    Table[T[n], {n, 1, 14}] // Flatten (* Jean-François Alcover, Oct 26 2015, after Alois P. Heinz *)

Extensions

Definition amended ('scattered' added) by Wouter Meeussen, Dec 22 2010

A182222 Number T(n,k) of standard Young tableaux of n cells and height >= k; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 4, 4, 3, 1, 10, 10, 9, 4, 1, 26, 26, 25, 16, 5, 1, 76, 76, 75, 56, 25, 6, 1, 232, 232, 231, 197, 105, 36, 7, 1, 764, 764, 763, 694, 441, 176, 49, 8, 1, 2620, 2620, 2619, 2494, 1785, 856, 273, 64, 9, 1, 9496, 9496, 9495, 9244, 7308, 3952, 1506, 400, 81, 10, 1
Offset: 0

Views

Author

Alois P. Heinz, Apr 19 2012

Keywords

Comments

Also number of self-inverse permutations in S_n with longest increasing subsequence of length >= k. T(4,3) = 4: 1234, 1243, 1324, 2134; T(3,0) = T(3,1) = 4: 123, 132, 213, 321; T(5,3) = 16: 12345, 12354, 12435, 12543, 13245, 13254, 14325, 14523, 15342, 21345, 21354, 21435, 32145, 34125, 42315, 52341.

Examples

			T(4,3) = 4, there are 4 standard Young tableaux of 4 cells and height >= 3:
  +---+   +------+   +------+   +------+
  | 1 |   | 1  2 |   | 1  3 |   | 1  4 |
  | 2 |   | 3 .--+   | 2 .--+   | 2 .--+
  | 3 |   | 4 |      | 4 |      | 3 |
  | 4 |   +---+      +---+      +---+
  +---+
Triangle T(n,k) begins:
    1;
    1,   1;
    2,   2,   1;
    4,   4,   3,   1;
   10,  10,   9,   4,   1;
   26,  26,  25,  16,   5,   1;
   76,  76,  75,  56,  25,   6,  1;
  232, 232, 231, 197, 105,  36,  7,  1;
  764, 764, 763, 694, 441, 176, 49,  8,  1;
  ...
		

Crossrefs

Diagonal and lower diagonals give: A000012, A000027(n+1), A000290(n+1) for n>0, A131423(n+1) for n>1.
T(2n,n) gives A318289.

Programs

  • Maple
    h:= proc(l) local n; n:=nops(l); add(i, i=l)! /mul(mul(1+l[i]-j+
           add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n)
        end:
    g:= proc(n, i, l) option remember;
          `if`(n=0, h(l), `if`(i<1, 0, `if`(i=1, h([l[], 1$n]),
            g(n, i-1, l) +`if`(i>n, 0, g(n-i, i, [l[], i])))))
        end:
    T:= (n, k)-> g(n, n, []) -`if`(k=0, 0, g(n, k-1, [])):
    seq(seq(T(n, k), k=0..n), n=0..12);
  • Mathematica
    h[l_] := Module[{n = Length[l]}, Sum[i, {i, l}]! / Product[ Product[1 + l[[i]] - j + Sum [If[l[[k]] >= j, 1, 0], {k, i+1, n}], {j, 1, l[[i]]}], {i, 1, n}]];
    g[n_, i_, l_] := g[n, i, l] = If[n == 0, h[l], If[i < 1, 0, If[i == 1, h[Join[l, Array[1&, n]]], g [n, i-1, l] + If[i > n, 0, g[n-i, i, Append[l, i]]]]]];
    t[n_, k_] := g[n, n, {}] - If[k == 0, 0, g[n, k-1, {}]];
    Table[Table[t[n, k], {k, 0, n}], {n, 0, 12}] // Flatten (* Jean-François Alcover, Dec 12 2013, translated from Maple *)

Formula

T(n,k) = A182172(n,n) - A182172(n,k-1) for k>0, T(n,0) = A182172(n,n).
Showing 1-3 of 3 results.