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A129843
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a(n) = number of positive integers which are <= n and are coprime to n!! (n!! = A006882(n)).
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0
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1, 1, 2, 2, 3, 2, 3, 3, 4, 2, 4, 3, 4, 3, 4, 3, 5, 4, 5, 5, 5, 4, 5, 5, 5, 4, 5, 4, 5, 5, 5, 6, 6, 5, 6, 5, 6, 5, 6, 5, 6, 6, 6, 7, 6, 6, 6, 7, 6, 7, 6, 7, 6, 8, 6, 8, 6, 7, 6, 8, 6, 8, 6, 8, 7, 8, 7, 9, 7, 9, 7, 10, 7, 10, 7, 10, 7, 10, 7, 11
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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MATHEMATICA
| a[n_]:=Module[{}, co=0; For[i=1, i<n+1, i++, If[GCD[n!!, i]==1, co++ ]]; co]; Table[a[n], {n, 1, 80}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 05 2007
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CROSSREFS
| Sequence in context: A105264 A063787 A182745 * A050430 A071330 A092333
Adjacent sequences: A129840 A129841 A129842 * A129844 A129845 A129846
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet Jun 03 2007
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EXTENSIONS
| More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 05 2007
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