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193, 202, 673, 1153, 1201, 1354, 1601, 1642, 1873, 2017, 2088, 2593, 2682, 2753, 3049, 3112, 3217, 3313, 3328, 3754, 3898, 4041, 4084, 4177, 4273, 4337, 4426, 4561, 5193, 5233, 5386, 5449, 5482, 5849, 6337, 6353, 6826, 6922, 7002, 7057, 7114, 7393, 7402, 7537, 7793, 8081, 8104, 8353, 8564, 8698, 8872, 9049, 9377, 9601
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OFFSET
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1,1
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COMMENTS
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That the first part of the condition is necessary for odd perfect numbers, see A332228, that the second part of the condition is necessary, see A019283 and A326181.
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LINKS
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PROG
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(PARI) isA332457(n) = { my(s=sigma(n)); ((2==(s%8)) && (6==(sigma(s)%8))); };
(Magma) [k:k in [1..9700]| DivisorSigma(1, k) mod 8 eq 2 and DivisorSigma(1, DivisorSigma(1, k)) mod 8 eq 6]; // Marius A. Burtea, Feb 15 2020
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CROSSREFS
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Cf. A332458 (a subsequence of non-primepower odd terms).
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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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