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.

Showing 1-7 of 7 results.

A214021 Number A(n,k) of n X k nonconsecutive tableaux; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 2, 1, 1, 1, 0, 1, 6, 6, 1, 1, 1, 0, 1, 22, 72, 18, 1, 1, 1, 0, 1, 92, 1289, 960, 57, 1, 1, 1, 0, 1, 422, 29889, 93964, 14257, 186, 1, 1, 1, 0, 1, 2074, 831174, 13652068, 8203915, 228738, 622, 1, 1
Offset: 0

Views

Author

Alois P. Heinz, Jul 01 2012

Keywords

Comments

A standard Young tableau (SYT) where entries i and i+1 never appear in the same row is called a nonconsecutive tableau.

Examples

			A(2,4) = 1:
  [1 3 5 7]
  [2 4 6 8].
A(4,2) = 6:
  [1, 5]   [1, 4]   [1, 3]   [1, 4]   [1, 3]   [1, 3]
  [2, 6]   [2, 6]   [2, 6]   [2, 5]   [2, 5]   [2, 4]
  [3, 7]   [3, 7]   [4, 7]   [3, 7]   [4, 7]   [5, 7]
  [4, 8]   [5, 8]   [5, 8]   [6, 8]   [6, 8]   [6, 8].
Square array A(n,k) begins:
  1, 1,  1,     1,       1,          1,              1, ...
  1, 1,  0,     0,       0,          0,              0, ...
  1, 1,  1,     1,       1,          1,              1, ...
  1, 1,  2,     6,      22,         92,            422, ...
  1, 1,  6,    72,    1289,      29889,         831174, ...
  1, 1, 18,   960,   93964,   13652068,     2621897048, ...
  1, 1, 57, 14257, 8203915, 8134044455, 11865331748843, ...
		

Crossrefs

Rows n=0+2, 3-4 give: A000012, A001181(k) for k>0, A214875.
Columns k=0+1, 2, 3 give: A000012, A000957(n+1), A214159.
Main diagonal gives A264103.

Programs

  • Maple
    b:= proc(l, t) option remember; local n, s; n, s:= nops(l),
           add(i, i=l); `if`(s=0, 1, add(`if`(t<>i and l[i]>
          `if`(i=n, 0, l[i+1]), b(subsop(i=l[i]-1, l), i), 0), i=1..n))
        end:
    A:= (n, k)-> `if`(n<1 or k<1, 1, b([k$n], 0)):
    seq(seq(A(n, d-n), n=0..d), d=0..12);
  • Mathematica
    b[l_, t_] := b[l, t] = Module[{n, s}, {n, s} = {Length[l], Sum[i, {i, l}]}; If[s == 0, 1, Sum[If[t != i && l[[i]] > If[i == n, 0, l[[i+1]]], b[ReplacePart[l, i -> l[[i]]-1], i], 0], {i, 1, n}]] ] ; a[n_, k_] := If[n < 1 || k < 1, 1, b[Array[k&, n], 0]]; Table[Table[a[n, d - n], {n, 0, d}], {d, 0, 12}] // Flatten (* Jean-François Alcover, Dec 09 2013, translated from Maple *)

A214020 Number A(n,k) of n X k chess tableaux; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 2, 0, 1, 1, 1, 1, 2, 6, 6, 2, 1, 1, 1, 1, 0, 22, 0, 22, 0, 1, 1, 1, 1, 5, 92, 324, 324, 92, 5, 1, 1, 1, 1, 0, 422, 0, 8716, 0, 422, 0, 1, 1, 1, 1, 14, 2074, 47570, 343234, 343234, 47570, 2074, 14, 1, 1
Offset: 0

Views

Author

Alois P. Heinz, Jul 01 2012

Keywords

Comments

A standard Young tableau (SYT) with cell(i,j)+i+j == 1 mod 2 for all cells is called a chess tableau. The definition appears first in the article by Jonas Sjöstrand.

Examples

			A(4,3) = A(3,4) = 6:
  [1 4  7]  [1 4  5]  [1 2  3]  [1 4  7]  [ 1  4  7]  [ 1  2  3]
  [2 5 10]  [2 7 10]  [4 7 10]  [2 5 10]  [ 2  5  8]  [ 4  5  6]
  [3 8 11]  [3 8 11]  [5 8 11]  [3 6 11]  [ 3  6  9]  [ 7  8  9]
  [6 9 12]  [6 9 12]  [6 9 12]  [8 9 12]  [10 11 12]  [10 11 12].
Square array A(n,k) begins:
  1,  1,  1,   1,     1,        1,          1,             1, ...
  1,  1,  1,   1,     1,        1,          1,             1, ...
  1,  1,  0,   1,     0,        2,          0,             5, ...
  1,  1,  1,   2,     6,       22,         92,           422, ...
  1,  1,  0,   6,     0,      324,          0,         47570, ...
  1,  1,  2,  22,   324,     8716,     343234,      17423496, ...
  1,  1,  0,  92,     0,   343234,          0,    8364334408, ...
  1,  1,  5, 422, 47570, 17423496, 8364334408, 6873642982160, ...
		

Crossrefs

Cf. A000108 (bisection of row 2), A001181 (row 3), A108774, A214021, A214088.

Programs

  • Maple
    b:= proc() option remember; local s; s:= add(i, i=args); `if`(s=0, 1,
          add(`if`(irem(s+i-args[i], 2)=1 and args[i]>`if`(i=nargs, 0,
          args[i+1]), b(subsop(i=args[i]-1, [args])[]), 0), i=1..nargs))
        end:
    A:= (n, k)-> `if`(n
    				
  • Mathematica
    b[args_List] := b[args] = Module[{s = Total[args], nargs = Length[args]}, If[s == 0, 1, Sum[If[Mod[s + i - args[[i]], 2] == 1 && args[[i]] > If[i == nargs, 0, args[[i + 1]]], b[ReplacePart[args, i -> args[[i]] - 1]], 0], {i, 1, nargs}]]]; A[n_, k_] := If[n < k, A[k, n], If[k < 2, 1, b[Array[n &, k]]]]; Table[Table[A[n, d - n], {n, 0, d}], {d, 0, 12}] // Flatten (* Jean-François Alcover, Jan 21 2015, after Alois P. Heinz *)

A214459 Number of n X 3 nonconsecutive chess tableaux.

Original entry on oeis.org

1, 0, 0, 1, 1, 7, 27, 128, 640, 3351, 18313, 103404, 600538, 3571717, 21683185, 134005373, 841259885, 5355078350, 34512405410, 224908338137, 1480420941781, 9833512593113, 65860442383487, 444453988418791, 3020274890688447, 20656019108074552, 142107550142684602
Offset: 0

Views

Author

Alois P. Heinz, Jul 18 2012

Keywords

Comments

A standard Young tableau (SYT) with cell(i,j)+i+j == 1 mod 2 for all cells where entries m and m+1 never appear in the same row is called a nonconsecutive chess tableau.

Examples

			a(5) = 7:
  [1  6 11] [1  4 11] [1  6  9] [1  4  9] [1  4  7] [1  4  7] [1  4  7]
  [2  7 12] [2  5 12] [2  7 10] [2  5 10] [2  5 10] [2  5 10] [2  5  8]
  [3  8 13] [3  8 13] [3  8 13] [3  8 13] [3  8 13] [3  6 13] [3 10 13]
  [4  9 14] [6  9 14] [4 11 14] [6 11 14] [6 11 14] [8 11 14] [6 11 14]
  [5 10 15] [7 10 15] [5 12 15] [7 12 15] [9 12 15] [9 12 15] [9 12 15].
		

Crossrefs

Column k=3 of A214088.

Programs

  • Maple
    b:= proc(l, t) option remember; local n, s;
           n, s:= nops(l), add(i, i=l);
          `if`(s=0, 1, add(`if`(t<>i and irem(s+i-l[i], 2)=1 and l[i]>
          `if`(i=n, 0, l[i+1]), b(subsop(i=l[i]-1, l), i), 0), i=1..n))
        end:
    a:= n-> b([3$n], 0):
    seq(a(n), n=0..25);
  • Mathematica
    b[l_, t_] := b[l, t] = Module[{n, s}, {n, s} = {Length[l], Sum[i, {i, l}]}; If[s == 0, 1, Sum[If[t != i && Mod[s + i - l[[i]], 2] == 1 && l[[i]] > If[i == n, 0, l[[i + 1]]], b[ReplacePart[l, {i -> l[[i]] - 1}], i], 0], {i, 1, n}]]]; a[n_] := If[n < 1, 1, b[Array[3&, n], 0]]; Table[a[n], {n, 0, 26}] (* Jean-François Alcover, Jul 13 2017, after Alois P. Heinz *)

Formula

a(n) ~ c * 8^n / n^4, where c = 0.250879571... - Vaclav Kotesovec, Sep 06 2017

A214460 Number of 4 X 2*n+1 nonconsecutive chess tableaux.

Original entry on oeis.org

1, 1, 1, 1, 2, 9, 44, 233, 1472, 10610, 82828, 688511, 6042580, 55523953, 530498426, 5242548633, 53361716373, 557495995958, 5961086843092, 65077096683358, 723862991146939, 8189257485453446, 94087399914391254, 1096331953010025684, 12941148147430923798
Offset: 0

Views

Author

Alois P. Heinz, Jul 18 2012

Keywords

Comments

A standard Young tableau (SYT) with cell(i,j)+i+j == 1 mod 2 for all cells where entries m and m+1 never appear in the same row is called a nonconsecutive chess tableau.

Examples

			a(4) = 2:
  [1, 4,  7, 12, 15, 20, 23, 28, 31]  [1,   4,  7, 10, 13, 16, 19, 22, 25]
  [2, 5, 10, 13, 18, 21, 26, 29, 34]  [2,   5,  8, 11, 14, 17, 28, 31, 34]
  [3, 8, 11, 16, 19, 24, 27, 32, 35]  [3,   6,  9, 20, 23, 26, 29, 32, 35]
  [6, 9, 14, 17, 22, 25, 30, 33, 36]  [12, 15, 18, 21, 24, 27, 30, 33, 36].
		

Crossrefs

Bisection (odd part) of row n=4 of A214088.

Programs

  • Maple
    b:= proc(l, t) option remember; local n, s;
           n, s:= nops(l), add(i, i=l);
          `if`(s=0, 1, add(`if`(t<>i and irem(s+i-l[i], 2)=1 and l[i]>
          `if`(i=n, 0, l[i+1]), b(subsop(i=l[i]-1, l), i), 0), i=1..n))
        end:
    a:= n-> b([(2*n+1)$4], 0):
    seq(a(n), n=0..25);
  • Mathematica
    b[l_List, t_] := b[l, t] = Module[{n, s}, {n, s} = {Length[l], Total[l]}; If[s == 0, 1, Sum[If[t != i && Mod[s + i - l[[i]], 2] == 1 && l[[i]] > If[i == n, 0, l[[i+1]]], b[ReplacePart[l, i -> l[[i]]-1], i], 0], {i, 1, n}]]]; a[n_] := b[{2n+1, 2n+1, 2n+1, 2n+1}, 0]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Jul 15 2017, translated from Maple *)

Formula

a(n) ~ c * 16^n / n^(15/2), where c = 5.347555... - Vaclav Kotesovec, Dec 05 2017

A214461 Number of 5 X n nonconsecutive chess tableaux.

Original entry on oeis.org

1, 1, 2, 7, 35, 212, 1421, 10128, 75724, 593905, 4927764, 43884083, 426665219, 4591883867, 54943702996, 725753304587, 10428313247758, 160361700765626, 2602492613187389, 44111609147837212, 775162479337156853, 14049351313802046511, 261640973700411314373
Offset: 0

Views

Author

Alois P. Heinz, Jul 18 2012

Keywords

Comments

A standard Young tableau (SYT) with cell(i,j)+i+j == 1 mod 2 for all cells where entries m and m+1 never appear in the same row is called a nonconsecutive chess tableau.

Examples

			a(3) = 7:
  [1  6 11] [1  4 11] [1  6  9] [1  4  9] [1  4  7] [1  4  7] [1  4  7]
  [2  7 12] [2  5 12] [2  7 10] [2  5 10] [2  5 10] [2  5 10] [2  5  8]
  [3  8 13] [3  8 13] [3  8 13] [3  8 13] [3  8 13] [3  6 13] [3 10 13]
  [4  9 14] [6  9 14] [4 11 14] [6 11 14] [6 11 14] [8 11 14] [6 11 14]
  [5 10 15] [7 10 15] [5 12 15] [7 12 15] [9 12 15] [9 12 15] [9 12 15].
		

Crossrefs

Row n=5 of A214088.

Programs

  • Maple
    b:= proc(l, t) option remember; local n, s;
           n, s:= nops(l), add(i, i=l);
          `if`(s=0, 1, add(`if`(t<>i and irem(s+i-l[i], 2)=1 and l[i]>
          `if`(i=n, 0, l[i+1]), b(subsop(i=l[i]-1, l), i), 0), i=1..n))
        end:
    a:= n-> b([n$5], 0):
    seq(a(n), n=0..25);
  • Mathematica
    b[l_List, t_] := b[l, t] = With[{n = Length[l], s = Total[l]}, If[s == 0, 1, Sum[If[t != i && Mod[s + i - l[[i]], 2] == 1 && l[[i]] > If[i == n, 0, l[[i + 1]]], b[ReplacePart[l, i -> l[[i]] - 1], i], 0], {i, 1, n}]]]; a[n_] := b[Table[n, {5}], 0]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Jul 15 2017, translated from Maple *)

A238020 Number of nonconsecutive chess tableaux with n cells.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 4, 5, 10, 15, 33, 52, 126, 213, 537, 991, 2563, 5118, 13670, 29171, 81069, 180813, 525755, 1216996, 3693934, 8843831, 27797975, 69106326, 223116931, 577433770, 1903516721, 5136516772, 17257698892, 48388514996, 166022450140, 481137194184
Offset: 0

Views

Author

Alois P. Heinz, Feb 17 2014

Keywords

Comments

A standard Young tableau (SYT) with cell(i,j)+i+j == 1 mod 2 for all cells where entries m and m+1 never appear in the same row is called a nonconsecutive chess tableau.

Examples

			a(6) = 4:
[1]   [1 6]   [1 4]   [1 4]
[2]   [2]     [2 5]   [2 5]
[3]   [3]     [3]     [3 6]
[4]   [4]     [6]
[5]   [5]
[6]
		

Crossrefs

Programs

  • Maple
    b:= proc(l, t) option remember; local n, s;
          n, s:= nops(l), add(i, i=l); `if`(s=0, 1, add(`if`(t<>i and
          irem(s+i-l[i], 2)=1 and l[i]>`if`(i=n, 0, l[i+1]), b(subsop(
          i=`if`(i=n and l[n]=1, [][], l[i]-1), l), i), 0), i=1..n))
        end:
    g:= (n, i, l)-> `if`(n=0 or i=1, b([l[], 1$n], 0), `if`(i<1, 0,
                     add(g(n-i*j, i-1, [l[], i$j]), j=0..n/i))):
    a:= n-> g(n, n, []):
    seq(a(n), n=0..32);
  • Mathematica
    b[l_, t_] := b[l, t] = Module[{ n = Length[l], s = Total[l]}, If[s == 0, 1, Sum[If[t != i && Mod[s + i - l[[i]], 2] == 1 && l[[i]] > If[i == n, 0, l[[i + 1]]], b[ReplacePart[l, i -> If[i == n && l[[n]] == 1, Nothing, l[[i]] - 1]], i], 0], {i, 1, n}]]];
    g[n_, i_, l_] := If[n == 0 || i == 1, b[Join[l, Table[1, n]], 0], If[i < 1, 0, Sum[g[n - i*j, i - 1, Join[l, Table[i, j]]], {j, 0, n/i}]]];
    a[n_] := g[n, n, {}];
    Table[a[n], {n, 0, 32}] (* Jean-François Alcover, Nov 08 2017, after Alois P. Heinz *)

A238184 Sum of the squares of numbers of nonconsecutive chess tableaux over all partitions of n.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 4, 7, 16, 37, 107, 282, 1020, 2879, 12507, 39347, 179231, 687974, 3225246, 14955561, 75999551, 392585613, 2271201137, 12183159188, 81562521256, 446611878413, 3336304592155, 19202329389234, 152803821604669, 958953289839930, 7835058287650579
Offset: 0

Views

Author

Alois P. Heinz, Feb 19 2014

Keywords

Comments

A standard Young tableau (SYT) with cell(i,j)+i+j == 1 mod 2 for all cells where entries m and m+1 never appear in the same row is called a nonconsecutive chess tableau.

Examples

			a(7) = 1 + 2^2 + 1 + 1 = 7:
.
: [1111111] :   [22111]    : [3211]  :  [322]  : <- shapes
:-----------+--------------+---------+---------:
:    [1]    : [1 6]  [1 4] : [1 4 7] : [1 4 7] :
:    [2]    : [2 7]  [2 5] : [2 5]   : [2 5]   :
:    [3]    : [3]    [3]   : [3]     : [3 6]   :
:    [4]    : [4]    [6]   : [6]     :         :
:    [5]    : [5]    [7]   :         :         :
:    [6]    :              :         :         :
:    [7]    :              :         :         :
		

Crossrefs

Programs

  • Maple
    b:= proc(l, t) option remember; local n, s;
          n, s:= nops(l), add(i, i=l); `if`(s=0, 1, add(`if`(t<>i and
          irem(s+i-l[i], 2)=1 and l[i]>`if`(i=n, 0, l[i+1]), b(subsop(
          i=`if`(i=n and l[n]=1, [][], l[i]-1), l), i), 0), i=1..n))
        end:
    g:= (n, i, l)-> `if`(n=0 or i=1, b([l[], 1$n], 0)^2, `if`(i<1, 0,
                     add(g(n-i*j, i-1, [l[], i$j]), j=0..n/i))):
    a:= n-> g(n, n, []):
    seq(a(n), n=0..32);
  • Mathematica
    b[l_, t_] := b[l, t] = Module[{n, s}, {n, s} = {Length[l], Total[l]}; If[s == 0, 1, Sum[If[t != i && Mod[s+i-l[[i]], 2] == 1 && l[[i]] > If[i==n, 0, l[[i+1]]], b[ReplacePart[l, i -> If[i==n && l[[n]]==1, Nothing, l[[i]]-1]], i], 0], {i, 1, n}]]]; g[n_, i_, l_] := g[n, i, l] = If[n==0 || i==1, b[Join[l, Array[1&, n]], 0]^2, If[i<1, 0, Sum[g[n-i*j, i-1, Join[l, Array[i&, j]]], {j, 0, n/i}]]]; a[n_] := g[n, n, {}]; Table[a[n], {n, 0, 32}] (* Jean-François Alcover, Feb 17 2017, translated from Maple *)

Formula

a(n) = Sum_{lambda : partitions(n)} ncc(lambda)^2, where ncc(k) is the number of nonconsecutive chess tableaux of shape k.
Showing 1-7 of 7 results.