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A109435
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Triangle read by rows: T(n,m) = number of binary numbers n digits long, which have m 0's as a substring.
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2
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1, 2, 1, 4, 3, 1, 8, 7, 3, 1, 16, 15, 8, 3, 1, 32, 31, 19, 8, 3, 1, 64, 63, 43, 20, 8, 3, 1, 128, 127, 94, 47, 20, 8, 3, 1, 256, 255, 201, 107, 48, 20, 8, 3, 1, 512, 511, 423, 238, 111, 48, 20, 8, 3, 1, 1024, 1023, 880, 520, 251, 112, 48, 20, 8, 3, 1, 2048, 2047, 1815, 1121, 558
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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G.f. for column m: x^m/( (1 - Sum_{k=1..m} x^k)*(1-2*x) ). - Geoffrey Critzer, Jan 07 2014
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EXAMPLE
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Triangle begins:
n\m_0__1__2__3__4__5
0| 1 0 0 0 0 0
1| 2 1 0 0 0 0
2| 4 3 1 0 0 0
3| 8 7 3 1 0 0
4| 16 15 8 3 1 0
5| 32 31 19 8 3 1
T(5,3)=8 because there are 8 length 5 binary words that contain 000 as a contiguous substring: 00000, 00001, 00010, 00011, 01000, 10000, 10001, 11000. - Geoffrey Critzer, Jan 07 2014
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MATHEMATICA
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T[n_, m_] := Length[ Select[ StringPosition[ #, StringDrop[ ToString[10^m], 1]] & /@ Table[ ToString[ FromDigits[ IntegerDigits[i, 2]]], {i, 2^n, 2^(n + 1) - 1}], # != {} &]]; Flatten[ Table[ T[n, m], {n, 0, 11}, {m, 0, n}]]
nn=15; Map[Select[#, #>0&]&, Transpose[Table[CoefficientList[Series[x^m/(1-Sum[x^k, {k, 1, m}])/(1-2x), {x, 0, nn}], x], {m, 0, nn}]]]//Grid (* Geoffrey Critzer, Jan 07 2014 *)
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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