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Search: id:A065385
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| A065385 |
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Numbers at which value of cototient function[A051953] reaches a new record: cototient[a(n)] > cototient[a(k)] for all a(k)<a(n). |
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3
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| 1, 2, 4, 6, 10, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90, 102, 108, 114, 120, 126, 132, 138, 144, 150, 168, 180, 198, 204, 210, 240, 252, 264, 270, 294, 300, 330, 360, 378, 390, 420, 450, 462, 480, 504, 510, 540, 546, 570, 600, 630, 660, 690, 714
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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For totient values prime numbers give similar records.
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FORMULA
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a=0; s=0; Do[s=n-EulerPhi[n]; If[s>a, a=s; Print[n]], {n, 1, 10000}]
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EXAMPLE
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a(8) = 30 because for m = 1...29 the cototient values are all smaller than cototient(30) = 22 = A065386(8) and this is the 8th number at which such a record is reached; analogous sequences are A002093, A002182, A015702 or A005250 for functions other than cototient.
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PROGRAM
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(PARI) r=-1; for(n=1, 1000, d=n-eulerphi(n); if(r<d, r=d; print1(n, ", ")))
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CROSSREFS
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Cf. A051953, A065386.
Adjacent sequences: A065382 A065383 A065384 this_sequence A065386 A065387 A065388
Sequence in context: A002491 A045958 A076067 this_sequence A055235 A083887 A064374
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Nov 05 2001
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