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.

A219356 Triangle read by rows: A219274 with rows reversed.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 3, 1, 4, 5, 1, 5, 9, 16, 1, 6, 14, 49, 1, 7, 20, 92, 70, 1, 8, 27, 153, 204, 168, 1, 9, 35, 235, 405, 738, 768, 1, 10, 44, 341, 715, 1815, 3300, 1, 11, 54, 474, 1166, 3630, 9460, 7887, 1, 12, 65, 637, 1794, 6578, 21307, 28743, 15015
Offset: 0

Views

Author

Alois P. Heinz, Nov 18 2012

Keywords

Comments

For more information see A219274.

Examples

			A219274 with rows reversed begins:
  1;
  1;
  1;
  1,  2;
  1,  3;
  1,  4,  5;
  1,  5,  9,  16;
  1,  6, 14,  49;
  1,  7, 20,  92,  70;
  1,  8, 27, 153, 204, 168;
  1,  9, 35, 235, 405, 738, 768;
  ...
		

Crossrefs

Row lengths are A122797 (for n>0).
Row sums give: A218293.
Last elements of rows give: A219339.

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) local s; s:=i*(i+1)/2;
          `if`(n=s, h([l[], seq(i-j, j=0..i-1)]), `if`(n>s, 0,
           g(n, i-1, l)+ `if`(i>n, 0, g(n-i, i-1, [l[], i]))))
        end:
    T:= (n, k)-> `if`(k>n, 0, g(n-k, k-1, [k])):
    seq(seq(T(n, n-k), k=0..(n-floor(sqrt(2*n)+1/2))), n=0..14);

A005118 Number of simple allowable sequences on 1..n containing the permutation 12...n.

Original entry on oeis.org

1, 1, 1, 2, 16, 768, 292864, 1100742656, 48608795688960, 29258366996258488320, 273035280663535522487992320, 44261486084874072183645699204710400, 138018895500079485095943559213817088756940800
Offset: 0

Views

Author

Keywords

Comments

For n >= 2 by the hook length formula a(n) is also the number of Young tableaux of size 1+2+...+(n-1) = n*(n-1)/2 that correspond to the partition (1,2,...n-1), i.e., triangular Young tableaux. For example, for n=5 the shape of the tableau is xxxx / xxx / xx / x. - Ahmed Fares (ahmedfares(AT)my-deja.com), May 04 2001
Also, a(n) is the degree of the symplectic Grassmannian, the projective variety of all maximal isotropic subspaces in a complex vector space of dimension 2n-2 with a symplectic form. See Hiller's paper. - Burt Totaro (b.totaro(AT)dpmms.cam.ac.uk), Oct 29 2002
Also, for n >= 2, a(n) is the number of maximal chains in the poset of Dyck paths ordered by inclusion. - Jennifer Woodcock (Jennifer.Woodcock(AT)ugdsb.on.ca), May 21 2008
a(n) is the number of minimal decompositions of the "flip" permutation n(n-1)..21 in terms of the n-1 standard Coxeter generators (i i+1) ("reduced decompositions", cf. Stanley). As such, it is also the number of positive n-strand braid words representing the Garside braid Delta(n) (the half-turn) (cf. Epstein's book, lemma 9.1.14). - Maxime Bourrigan, Apr 04 2011
For n >= 1, the normalized volume of the subpolytope of the Birkhoff polytope obtained by taking the convex hull of all (2n)x(2n) permutation matrices corresponding to alternating permutations that also avoid the pattern 123. - Robert Davis, Dec 04 2016

References

  • D. B. A. Epstein with J. W. Cannon, D. F. Holt, S. V. F. Levy, M. S. Paterson and W. P. Thurston, Word Processing in Groups, Jones and Bartlett Publishers, Boston, MA, 1992. xii+330 pp.
  • J. E. Goodman and J. O'Rourke, editors, Handbook of Discrete and Computational Geometry, CRC Press, 1997, p. 102.
  • G. Kreweras, Sur un problème de scrutin à plus de deux candidats, Publications de l'Institut de Statistique de l'Université de Paris, 26 (1981), 69-87.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Maple
    A005118 := proc(n) local i; binomial(n,2)!/product( (2*i+1)^(n-i-1), i=0..n-2 ); end;
  • Mathematica
    Table[Binomial[n, 2]!/Product[(2*i + 1)^(n - i - 1), {i, 0, n - 2}], {n, 0, 10}] (* T. D. Noe, May 29 2012 *)

Formula

a(n) = C(n, 2)!/(1^{n-1} * 3^{n-2} *...* (2n-3)^1 ).
a(n) = (n*(n-1)/2)!/A057863(n-1) (n>=1). - Emeric Deutsch, May 21 2004
a(n) = A153452(A002110(n-1)). - Naohiro Nomoto, Jan 01 2009
From Alois P. Heinz, Nov 18 2012: (Start)
a(n+1) = A219272(A000217(n),n) = A219274(A000217(n),n) = A219311(A000217(n),n).
a(n) = A193536(n,A000217(n-1)) = A193629(n,A000217(n-1)). (End)
a(n) ~ sqrt(Pi) * n^(n^2/2-n/2+23/24) * exp(n^2/4-n/2+7/24) / (A^(1/2) * 2^(n^2-n/2-7/24)), where A = 1.2824271291... is the Glaisher-Kinkelin constant (see A074962). - Vaclav Kotesovec, Nov 13 2014

Extensions

Citation corrected by Matthew J. Samuel, Feb 01 2011

A218293 Number of standard Young tableaux with shapes corresponding to partitions into distinct parts.

Original entry on oeis.org

1, 1, 1, 3, 4, 10, 31, 70, 190, 561, 2191, 6226, 22683, 74152, 283349, 1211354, 4572672, 18844177, 77585825, 327472752, 1418056071, 7083303437, 31251988918, 153456264178, 723293387594, 3596567095155, 17360616601051, 89955643932801, 486526881887485, 2551613423040841, 14029592127656040, 76756835252971657, 428044848852530252
Offset: 0

Views

Author

Joerg Arndt, Oct 25 2012

Keywords

Crossrefs

Cf. A000085 (standard Young tableaux for all shapes).
Diagonal of A219272, row sums of A219274, A219311. - Alois P. Heinz, Nov 17 2012
Cf. A225121 (tableaux with shapes corresponding to partitions into distinct parts with minimal difference 2).

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) local s; s:=i*(i+1)/2;
          `if`(n=s, h([l[], seq(i-j, j=0..i-1)]), `if`(n>s, 0,
           g(n, i-1, l)+ `if`(i>n, 0, g(n-i, i-1, [l[], i]))))
        end:
    a:= n-> g(n, n, []):
    seq(a(n), n=0..40);  # Alois P. Heinz, Nov 08 2012
  • Mathematica
    h[l_List] := Module[{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_List] := Module[{s=i*(i+1)/2}, If[n == s, h[Join[l, Table[i-j, {j, 0, i-1}]]], If[n > s, 0, g[n, i-1, l] + If[i>n, 0, g[n-i, i-1, Append[l, i]]]]]]; a[n_] := g[n, n, {}]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Feb 18 2015, after Alois P. Heinz *)

A219311 Number T(n,k) of standard Young tableaux for partitions of n into exactly k distinct parts; triangle T(n,k), n>=0, 0<=k<=A003056(n), read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 0, 1, 2, 0, 1, 3, 0, 1, 9, 0, 1, 14, 16, 0, 1, 34, 35, 0, 1, 55, 134, 0, 1, 125, 435, 0, 1, 209, 1213, 768, 0, 1, 461, 3454, 2310, 0, 1, 791, 10484, 11407, 0, 1, 1715, 28249, 44187, 0, 1, 3002, 80302, 200044, 0, 1, 6434, 231895, 680160, 292864
Offset: 0

Views

Author

Alois P. Heinz, Nov 17 2012

Keywords

Comments

T(n,k) is defined for n,k >= 0. The triangle contains only the terms with k<=A003056(n). T(n,k) = 0 for k>A003056(n).

Examples

			A(4,2) = 3:
  +---------+  +---------+  +---------+
  | 1  2  3 |  | 1  2  4 |  | 1  3  4 |
  | 4 .-----+  | 3 .-----+  | 2 .-----+
  +---+        +---+        +---+
Triangle T(n,k) begins:
  1;
  0,  1;
  0,  1;
  0,  1,    2;
  0,  1,    3;
  0,  1,    9;
  0,  1,   14,    16;
  0,  1,   34,    35;
  0,  1,   55,   134;
  0,  1,  125,   435;
  0,  1,  209,  1213,   768;
  0,  1,  461,  3454,  2310;
  0,  1,  791, 10484, 11407;
  ...
		

Crossrefs

Columns k=0-10 give: A000007, A000012 (for n>0), A047171(n) = A037952(n)-1, A219316, A219317, A219318, A219319, A219320, A219321, A219322, A219323.
Row sums give: A218293.
Row lengths are 1 + A003056(n).
T(A000217(k),k) = A005118(k+1).

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, k, l) `if`(n=0, h(l), `if`(n>k*(i-(k-1)/2), 0,
          g(n, i-1, min(k, i-1), l)+`if`(i>n, 0, g(n-i, i-1, k-1, [l[], i]))))
        end:
    A:= proc(n, k) option remember; `if`(k<0, 0, g(n, n, k, [])) end:
    T:= (n, k)-> A(n, k) -A(n, k-1):
    seq(seq(T(n, k), k=0..floor((sqrt(1+8*n)-1)/2)), n=0..20);
  • Mathematica
    h[l_] := With[{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_, k_, l_] := If[n == 0, h[l], If[n > k*(i-(k-1)/2), 0, g[n, i-1, Min[k, i-1], l] + If[i > n, 0, g[n-i, i-1, k-1, Append[l, i]]]]];
    a[n_, k_] := a[n, k] = If[k < 0, 0, g[n, n, k, {}]];
    t[n_, k_] := a[n, k] - a[n, k-1];
    Table[Table[t[n, k], {k, 0, Floor[(Sqrt[1+8*n]-1)/2]}], {n, 0, 20}] // Flatten (* Jean-François Alcover, Dec 17 2013, translated from Maple *)

A219272 Number A(n,k) of standard Young tableaux for partitions of n into distinct parts with largest part <= k; triangle A(n,k), k>=0, 0<=n<=k*(k+1)/2, read by columns.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 3, 5, 16, 1, 1, 1, 3, 4, 9, 25, 49, 70, 168, 768, 1, 1, 1, 3, 4, 10, 30, 63, 162, 372, 1506, 3300, 7887, 15015, 48048, 292864, 1, 1, 1, 3, 4, 10, 31, 69, 182, 525, 1911, 5115, 17347, 43758, 149721, 626769, 1946516, 4934930
Offset: 0

Views

Author

Alois P. Heinz, Nov 17 2012

Keywords

Comments

A(n,k) is defined for n,k >= 0. A(n,k) = 0 iff n > k*(k+1)/2 = A000217(k). The triangle contains only the nonzero terms. A(n,k) = A(n,n) for k>=n.

Examples

			A(3,2) = 2:
+------+  +------+
| 1  2 |  | 1  3 |
| 3 .--+  | 2 .--+
+---+     +---+
A(3,3) = 3:
+------+  +------+  +---------+
| 1  2 |  | 1  3 |  | 1  2  3 |
| 3 .--+  | 2 .--+  +---------+
+---+     +---+
Triangle A(n,k) begins:
1,  1,  1,  1,   1,    1,    1,    1,    1, ...
.   1,  1,  1,   1,    1,    1,    1,    1, ...
.       1,  1,   1,    1,    1,    1,    1, ...
.       2,  3,   3,    3,    3,    3,    3, ...
.           3,   4,    4,    4,    4,    4, ...
.           5,   9,   10,   10,   10,   10, ...
.          16,  25,   30,   31,   31,   31, ...
.               49,   63,   69,   70,   70, ...
.               70,  162,  182,  189,  190, ...
		

Crossrefs

Column heights are A000124.
Column sums give: A219273.
Diagonal gives: A218293.
Leftmost nonzero elements give A219339.
Column of leftmost nonzero element is A002024(n) for n>0.
T(A000217(n),n) = A005118(n+1).

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) local s; s:=i*(i+1)/2;
          `if`(n=s, h([l[], seq(i-j, j=0..i-1)]), `if`(n>s, 0,
           g(n, i-1, l)+ `if`(i>n, 0, g(n-i, i-1, [l[], i]))))
        end:
    A:= (n, k)-> g(n, k, []):
    seq(seq(A(n, k), n=0..k*(k+1)/2), k=0..7);
  • Mathematica
    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_] := g[n, i, l] = With[{s=i*(i+1)/2}, If[n==s, h[Join[l, Table[ i-j, {j, 0, i-1}]]], If[n>s, 0, g[n, i-1, l] + If[i>n, 0, g[n-i, i-1, Append[l, i]]]]]];
    A[n_, k_] := g[n, k, {}];
    Table[Table[A[n, k], {n, 0, k*(k+1)/2}], {k, 0, 7}] // Flatten (* Jean-François Alcover, Feb 29 2016, after Alois P. Heinz *)

Formula

T(n,k) = Sum_{i=0..k} A219274(n,i).

A219339 Number of standard Young tableaux for partitions of n into distinct parts with largest part floor(sqrt(2*n)+1/2).

Original entry on oeis.org

1, 1, 1, 2, 3, 5, 16, 49, 70, 168, 768, 3300, 7887, 15015, 48048, 292864, 1946516, 4934930, 14454726, 34918884, 141892608, 1100742656, 9732668946, 32773404950, 97848532782, 344699731090, 1020872973120, 5091106775040, 48608795688960, 586393249199550
Offset: 0

Views

Author

Alois P. Heinz, Nov 18 2012

Keywords

Comments

a(n) is the leftmost nonzero element in row n of A219272, A219274.
Floor(sqrt(2*n)+1/2) = A002024(n) for n>0. There are no partitions of n into distinct parts with a smaller largest part.

Examples

			For n=5, we have floor(sqrt(2*n)+1/2) = 3, and a(5) = 5, because there are 5 standard Young tableaux for partitions of 5 into distinct parts with largest part 3:
+---------+  +---------+  +---------+  +---------+  +---------+
| 1  2  3 |  | 1  2  4 |  | 1  2  5 |  | 1  3  4 |  | 1  3  5 |
| 4  5 .--+  | 3  5 .--+  | 3  4 .--+  | 2  5 .--+  | 2  4 .--+
+------+     +------+     +------+     +------+     +------+
		

Crossrefs

Cf. A005118 (subsequence), A219347.

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) local s; s:=i*(i+1)/2;
          `if`(n=s, h([l[], seq(i-j, j=0..i-1)]), `if`(n>s, 0,
           g(n, i-1, l)+ `if`(i>n, 0, g(n-i, i-1, [l[], i]))))
        end:
    a:= n-> g(n, floor(sqrt(2*n)+1/2), []):
    seq(a(n), n=0..30);
  • Mathematica
    h[l_] := (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_] := g[n, i, l] = (s = i*(i+1)/2; If[n==s, h[Join[l, Table[i-j, {j, 0, i-1}]] ], If[n>s, 0, g[n, i-1, l]+If[i>n, 0, g[n-i, i-1, Append[l, i]]]]] ); a[n_] := g[n, Floor[Sqrt[2*n]+1/2], {}]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Feb 16 2017, translated from Maple *)

Formula

a(n) = A219272(n,floor(sqrt(2*n)+1/2)) = A219274(n,floor(sqrt(2*n)+1/2)).

A219275 Number of standard Young tableaux for partitions of nonnegative integers into distinct parts with largest part n.

Original entry on oeis.org

1, 1, 3, 25, 1069, 368168, 1299366501, 55208013380403, 32401197537296758130, 297072961835477978342245712, 47538199827835784548062928051198402, 146779873623344672821145371965795071455181183, 9581411392319396646028223743176779937161862866453789852
Offset: 0

Views

Author

Alois P. Heinz, Nov 17 2012

Keywords

Examples

			a(2) = 3:
+------+  +------+  +------+
| 1  2 |  | 1  3 |  | 1  2 |
| 3 .--+  | 2 .--+  +------+
+---+     +---+
		

Crossrefs

Column sums of A219274.
First differences of A219273.

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:
    b:= (n, l)-> `if`(n<1, h(l), b(n-1, l) +b(n-1, [l[], n])):
    a:= n-> `if`(n=0, 1, b(n-1, [n])):
    seq(a(n), n=0..12);
  • Mathematica
    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}]];
    b[n_, l_] := If[n < 1, h[l], b[n - 1, l] + b[n - 1, Append[l, n]]];
    a[n_] := If[n == 0, 1, b[n - 1, {n}]];
    Table[a[n], {n, 0, 12}] (* Jean-François Alcover, Nov 02 2022, after Alois P. Heinz *)
Showing 1-7 of 7 results.