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A264911
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Number of 6-ascent sequences of length n with no consecutive repeated letters.
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2
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1, 1, 6, 42, 315, 2541, 21931, 201761, 1971627, 20401115, 222886237, 2564378397, 30996823039, 392772620555, 5206946927601, 72084153595073, 1040323636265431, 15627180533214417, 243970019981427565, 3953119943277152705, 66394925299770846495, 1154518082416143179150
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OFFSET
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0,3
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LINKS
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MAPLE
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b:= proc(n, i, t) option remember; `if`(n<1, 1, add(
`if`(j=i, 0, b(n-1, j, t+`if`(j>i, 1, 0))), j=0..t+6))
end:
a:= n-> (b(n-1, 0$2)):
seq(a(n), n=0..30);
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MATHEMATICA
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b[n_, i_, t_] := b[n, i, t] = If[n < 1, 1, Sum[If[j == i, 0, b[n - 1, j, t + If[j > i, 1, 0]]], {j, 0, t + 6}]]; a[n_] := b[n - 1, 0, 0];
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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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