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A171257
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Numbers n such that sigma(n) = 11*phi(n) (where sigma=A000203, phi=A000010).
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5
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2580, 16770, 18630, 28896, 35970, 61404, 66024, 147576, 163944, 215124, 224010, 296184, 399126, 408672, 443394, 464340, 476010, 574308, 856086, 862752, 868428, 931224, 957348, 1004910, 1110186, 1496610, 1721720, 1723290, 1833348, 1971288, 2139852, 2234790
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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Select[Range[10^6], DivisorSigma[1, #] == 11 * EulerPhi[#] &] (* Amiram Eldar, Dec 04 2019 *)
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PROG
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(PARI) for(k=1, 2e6, sigma(k) - 11*eulerphi(k) | print1(k", "));
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CROSSREFS
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Cf. A062699, A068391, A068390, A136547, A104900, A136540, A104901, A163667, A171256, A104902, A171258, A171259, A171260, A104903.
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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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