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Search: id:A061884
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| A061884 |
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a(n) = Sum_{ d divides n } phi(lcm(d,n/d)), where phi(n) = Euler totient function, cf. A000010. |
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+0
3
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| 1, 2, 4, 5, 8, 8, 12, 12, 14, 16, 20, 20, 24, 24, 32, 26, 32, 28, 36, 40, 48, 40, 44, 48, 44, 48, 48, 60, 56, 64, 60, 56, 80, 64, 96, 70, 72, 72, 96, 96, 80, 96, 84, 100, 112, 88, 92, 104, 90, 88, 128, 120, 104, 96, 160, 144, 144, 112, 116, 160, 120, 120, 168, 116, 192
(list; graph; listen)
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OFFSET
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1,2
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MAPLE
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A061884 := proc(n) local b, d: b := 0; for d from 1 to n do if irem(n, d)=0 then b := b+phi(lcm(d, n/d)); fi; od; RETURN(b); end:
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MATHEMATICA
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Table[Plus @@ Map[ EulerPhi[LCM[ #, n/# ]] &, Select[ Range@n, (Mod[n, # ] == 0) &]], {n, 65}] (* Robert G. Wilson v Sep 30 2006 *)
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CROSSREFS
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Cf. A001616, A057670, A007427.
Sequence in context: A036699 A036694 A085624 this_sequence A029935 A123291 A099402
Adjacent sequences: A061881 A061882 A061883 this_sequence A061885 A061886 A061887
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), May 12 2001
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