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A007578 Number of Young tableaux of height <= 7.
(Formerly M1219)
11

%I M1219

%S 1,2,4,10,26,76,232,763,2611,9415,35135,136335,544623,2242618,9463508,

%T 40917803,180620411,813405580,3728248990,17377551032,82232982872,

%U 394742985974,1919885633178,9453682648281,47086636037601,237071351741426,1205689994416252

%N Number of Young tableaux of height <= 7.

%C Also the number of n-length words w over 7-ary alphabet {a1,a2,...,a7} such that for every prefix z of w we have #(z,a1) >= #(z,a2) >= ... >= #(z,a7), where #(z,x) counts the number of letters x in word z. - _Alois P. Heinz_, May 30 2012

%D F. Bergeron, L. Favreau and D. Krob, Conjectures on the enumeration of tableaux of bounded height, Discrete Math, vol. 139, no. 1-3 (1995), 463-468.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Alois P. Heinz, <a href="/A007578/b007578.txt">Table of n, a(n) for n = 1..400</a>

%H <a href="/index/Y#Young">Index entries for sequences related to Young tableaux.</a>

%F a(n) ~ 45/32 * 7^(n+21/2)/(Pi^(3/2)*n^(21/2)). - _Vaclav Kotesovec_, Sep 11 2013

%p h:= proc(l) local n; n:=nops(l);

%p add(i, i=l)! /mul (mul (1+l[i]-j +add (`if`(l[k]>=j, 1, 0),

%p k=i+1..n), j=1..l[i]), i=1..n)

%p end:

%p g:= proc(n, i, l) option remember;

%p `if`(n=0, h(l), `if`(i=1, h([l[], 1$n]), `if`(i<1, 0,

%p g(n, i-1, l) +`if`(i>n, 0, g(n-i, i, [l[], i])))))

%p end:

%p a:= n-> g(n, 7, []):

%p seq (a(n), n=1..30); # _Alois P. Heinz_, Apr 10 2012

%p # second Maple program

%p a:= proc(n) option remember;

%p `if`(n<4, [1, 1, 2, 4][n+1],

%p ((4*n^3+78*n^2+424*n+495)*a(n-1)

%p +(n-1)*(34*n^2+280*n+305)*a(n-2)

%p -2*(n-1)*(n-2)*(38*n+145)*a(n-3)

%p -105*(n-1)*(n-2)*(n-3)*a(n-4)) /

%p ((n+6)*(n+10)*(n+12)))

%p end:

%p seq (a(n), n=1..30); # _Alois P. Heinz_, Oct 12 2012

%t RecurrenceTable[{105 (-3+n) (-2+n) (-1+n) a[-4+n]+2 (-2+n) (-1+n) (145+38 n) a[-3+n]-(-1+n) (305+280 n+34 n^2) a[-2+n]+(-495-424 n-78 n^2-4 n^3) a[-1+n]+(6+n) (10+n) (12+n) a[n]==0,a[1]==1,a[2]==2,a[3]==4,a[4]==10}, a, {n, 20}] (* _Vaclav Kotesovec_, Sep 11 2013 *)

%Y Column k=7 of A182172. - _Alois P. Heinz_, May 30 2012

%K nonn

%O 1,2

%A _Simon Plouffe_

%E More terms from _Alois P. Heinz_, Apr 10 2012

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Last modified July 22 23:14 EDT 2014. Contains 244849 sequences.