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Search: id:A123041
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| A123041 |
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Numbers such that UnitarySigma(m)^2 = k*Sigma(m)*UnitaryPhi(m), for some integer k. |
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+0
2
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| 1, 2, 3, 6, 14, 15, 30, 35, 42, 70, 78, 105, 190, 210, 357, 418, 570, 714, 910, 1045, 1254, 1976, 2090, 2730, 3135, 4522, 4674, 5278, 5412, 5928, 6270, 8580, 10659, 12441, 12628, 13566, 14630, 15834, 16770, 17220, 20026, 21318, 23374, 24871, 24882
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Terms which are square-free appear on A121556.
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PROGRAM
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(PARI) A047994(n)={ local(i, resul, rmax); if(n==1, return(1) ); i=factor(n); rmax=matsize(i)[1]; resul=1; for(r=1, rmax, resul *= i[r, 1]^i[r, 2]-1; ); return(resul); } A034448(n)={ sumdiv(n, d, if(gcd(d, n/d)==1, d)) } isA123041(n)={ local(s); s=(A034448(n))^2; if( s % (sigma(n)*A047994(n)) == 0, return(s/sigma(n)/A047994(n)), return(0) ); } { for(n=1, 30000, k=isA123041(n); if( k, print1(n, ", ") ); ); } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 27 2006
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CROSSREFS
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Cf. A123042, A121556.
Sequence in context: A030733 A122839 A121556 this_sequence A078557 A005537 A087293
Adjacent sequences: A123038 A123039 A123040 this_sequence A123042 A123043 A123044
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KEYWORD
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nonn
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AUTHOR
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Yasutoshi Kohmoto zbi74583(AT)boat.zero.ad.jp, Sep 24 2006
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 27 2006
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