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A165629
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Numbers n such that sigma(n)/phi(n) = 25/4, where sigma = A000203, phi = A000010.
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1
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760, 11020, 18088, 21112, 58206, 65262, 71630, 100280, 123424, 142688, 262276, 303212, 332710, 630344, 679070, 761390, 1265096, 1369120, 1454060, 1454260, 1462552, 1704794, 2185750, 2386664, 2627548, 2783872, 2786056, 2909380, 2927848, 5207680, 5289220
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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Select[Range[5300000], 4*DivisorSigma[1, #]==25*EulerPhi[#]&] (* Harvey P. Dale, May 09 2012 *)
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PROG
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(PARI) for( i=1, 1e9, sigma(i)*4-25*eulerphi(i) || print1(i", "))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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