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Search: id:A133440
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| A133440 |
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a(1)=1. a(n) = sum{1<=k<=n, GCD(k,n)=1} floor(sqrt(k)). |
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+0
1
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| 1, 1, 2, 2, 5, 3, 9, 6, 10, 7, 19, 8, 25, 13, 17, 18, 38, 15, 46, 21, 33, 27, 62, 23, 58, 36, 56, 38, 90, 26, 100, 54, 69, 55, 84, 43, 131, 66, 90, 61, 155, 48, 167, 80, 97, 90, 191, 67, 178, 86, 139, 105, 231, 81, 181, 110, 166, 130, 273, 76, 287, 144, 175, 156, 235, 100
(list; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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The positive integers which are <12 and are coprime to 12 are 1,5,7,11. The floors of the squareroots of these are 1,2,2,3. So a(12) = 1+2+2+3 = 8.
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MATHEMATICA
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Table[Plus @@ (Floor[Sqrt[Select[Range[n], GCD[ #, n] == 1 &]]]), {n, 1, 70}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 01 2007
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CROSSREFS
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Adjacent sequences: A133437 A133438 A133439 this_sequence A133441 A133442 A133443
Sequence in context: A071939 A075545 A006307 this_sequence A006800 A113177 A135281
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Nov 26 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 01 2007
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