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A244298
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Number of standard Young tableaux with n cells such that the lengths of the first and the last row differ by 4.
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2
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5, 15, 119, 421, 2254, 8999, 40349, 166817, 737829, 3008774, 13186593, 54944783, 238422808, 1010671048, 4395831546, 18821162274, 82799233661, 359711480525, 1599420076729, 7030074945271, 31626819884986, 141486845119777, 646988113794544, 2940338763342920
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OFFSET
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6,1
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COMMENTS
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Also the number of ballot sequences of length n such that the multiplicities of the largest and the smallest value differ by 4.
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LINKS
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MAPLE
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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 j; `if`(n=0 or i<1, 0, `if`(l<>[] and
l[1]-i=4, `if`(irem(n, i, 'j')=0, h([l[], i$j]), 0),
add(g(n-i*j, i-1, [l[], i$j]), j=0..n/i)))
end:
a:= n-> g(n$2, []):
seq(a(n), n=6..35);
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MATHEMATICA
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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, l[[i]]}], {i, n}]];
g[n_, i_, l_] := Module[{j}, If[n == 0 || i < 1, 0, If[l != {} && l[[1]] - i == 4, If[j = Quotient[n, i]; Mod[n, i] == 0, h[Join[l, Table[i, {j}]]], 0], Sum[g[n - i*j, i - 1, Join[l, Table[i, {j}]]], {j, 0, n/i}]]]];
a[n_] := g[n, n, {}];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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