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A064314
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Total length of longest increasing runs in all permutations of n elements.
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2
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1, 3, 12, 55, 299, 1900, 13942, 115932, 1078361, 11092265, 125040100, 1532995992, 20310212672, 289186696338, 4404156016584, 71441907922793, 1229835421590959, 22393298253477006, 430019590699868644, 8685717780508953928, 184088653170341473400, 4085097253151506682170
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OFFSET
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1,2
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LINKS
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FORMULA
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MAPLE
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b:= proc(u, o, t, k) option remember; `if`(t=k, (u+o)!,
`if`(max(t, u)+o<k, 0, add(b(u+j-1, o-j, t+1, k), j=1..o)+
add(b(u-j, o+j-1, 1, k), j=1..u)))
end:
a:= n-> add(b(0, n, 0, k), k=1..n) -n*b(0, n, 0, n+1):
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MATHEMATICA
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nn=30; f[list_]:=Total[Table[list[[i]]*i, {i, 1, Length[list]}]]; a[r_]:=Apply[Plus, Table[Normal[Series[y x^(r+1)/(1-Sum[y x^i, {i, 1, r}]), {x, 0, nn}]][[n]]/(n+r)!, {n, 1, nn-r}]]/.y->-1; Map[f, Map[Select[#, #>0&]&, Transpose[Prepend[Table[Drop[Range[0, nn]! CoefficientList[Series[1/(1-x-a[n+1])-1/(1-x-a[n]), {x, 0, nn}], x], 1], {n, 1, 28}], Table[1, {nn}]]]]] (* Geoffrey Critzer, Feb 25 2014 *)
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CROSSREFS
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This sequence treats runs of adjacent elements, A003316 treats subsequences of not necessarily adjacent elements.
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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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