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.

A212915 Number of standard Young tableaux of n cells and height <= 9.

Original entry on oeis.org

1, 1, 2, 4, 10, 26, 76, 232, 764, 2620, 9495, 35685, 140031, 567503, 2382394, 10290308, 45780063, 208852719, 977152266, 4674398032, 22854255698, 113957313538, 579157509082, 2995214721530, 15752586526189, 84145056172981, 456221504976506, 2508227921637772
Offset: 0

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Author

Alois P. Heinz, May 30 2012

Keywords

Comments

Number of standard Young tableaux of n cells and <= 9 columns.
Also the number of n-length words w over 9-ary alphabet {a1,a2,...,a9} such that for every prefix z of w we have #(z,a1) >= #(z,a2) >= ... >= #(z,a9), where #(z,x) counts the letters x in word z.

Crossrefs

Column k=9 of A182172.

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, h([l[], 1$n]), `if`(i<1, 0,
            g(n, i-1, l) +`if`(i>n, 0, g(n-i, i, [l[], i])))))
        end:
    a:= n-> g(n, 9, []):
    seq(a(n), n=0..30);
    # second Maple program:
    a:= proc(n) option remember;
          `if`(n<5, [1, 1, 2, 4, 10][n+1],
          ((5*n^4+230*n^3+3574*n^2+20663*n+29393)*a(n-1)
           +7*(n-1)*(10*n^3+266*n^2+1919*n+2713)*a(n-2)
           -(n-1)*(n-2)*(230*n^2+3934*n+13587)*a(n-3)
           -3*(n-1)*(n-2)*(n-3)*(263*n+1414)*a(n-4)
           +945*(n-1)*(n-2)*(n-3)*(n-4)*a(n-5)) /
           ((n+20)*(n+8)*(n+18)*(n+14)))
        end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Oct 12 2012
  • Mathematica
    Flatten[{1,RecurrenceTable[{-945 (-4+n) (-3+n) (-2+n) (-1+n) a[-5+n]+3 (-3+n) (-2+n) (-1+n) (1414+263 n) a[-4+n]+(-2+n) (-1+n) (13587+3934 n+230 n^2) a[-3+n]-7 (-1+n) (2713+1919 n+266 n^2+10 n^3) a[-2+n]+(-29393-20663 n-3574 n^2-230 n^3-5 n^4) a[-1+n]+(8+n) (14+n) (18+n) (20+n) a[n]==0,a[1]==1,a[2]==2,a[3]==4,a[4]==10,a[5]==26}, a, {n, 20}]}] (* Vaclav Kotesovec, Sep 11 2013 *)

Formula

a(n) ~ 14175/256 * 9^(n+18)/(Pi^2*n^18). - Vaclav Kotesovec, Sep 11 2013