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Search: id:A129915
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| A129915 |
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Triangular sequence of when integers are of the form: factorial[n]=a(n)*2^m ;Sequence dividing the powers of two out of factorials. |
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+0
1
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| 1, 1, 1, 2, 3, 6, 3, 6, 12, 24, 15, 30, 60, 120, 45, 90, 180, 360, 720, 315, 630, 1260, 2520, 5040, 315, 630, 1260, 2520, 5040, 10080, 20160, 40320, 2835, 5670, 11340, 22680, 45360, 90720, 181440, 362880, 14175, 28350, 56700, 113400, 226800, 453600
(list; table; graph; listen)
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OFFSET
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1,4
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COMMENT
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A music scale like way of looking at symmetric and alternating group dimensions. Row sum is ( not in OEIS): Table[Apply[Plus, Reverse[Flatten[Table[If[IntegerQ[n!/2^m], n!/2^m, {}], {m, 0, n}]]]], {n, 0, 10}] {1, 1, 3, 9, 45, 225, 1395, 9765, 80325, 722925, 7243425} Also predicts a first row (minimum) sequence A049606: {1,1,3,3,15,45,315,315,2835,14175}
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FORMULA
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t(n,m) = If Integer( n!/2^m)
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EXAMPLE
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{1},
{1},
{1, 2},
{3, 6},
{3, 6, 12, 24},
{15, 30, 60, 120},
{45, 90, 180,360, 720},
{315, 630, 1260, 2520, 5040},
{315, 630, 1260, 2520, 5040, 10080, 20160, 40320}
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MATHEMATICA
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f[n_, m_] := If[IntegerQ[n!/2^m], n!/2^m, {}]; a = Table[Reverse[Flatten[Table[If[IntegerQ[n!/2^m], n!/2^m, {}], {m, 0, n}]]], {n, 0, 10}]; Flatten[a]
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CROSSREFS
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Cf. A049606, A067655.
Sequence in context: A115033 A093396 A084228 this_sequence A019773 A109536 A101401
Adjacent sequences: A129912 A129913 A129914 this_sequence A129916 A129917 A129918
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KEYWORD
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nonn,uned,tabl
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AUTHOR
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Roger L. Bagula (rlbagulatfttn(AT)yahoo.com), Jun 05 2007
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