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A241480
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Numbers such that the GCD of the x's that satisfy sigma(x)=sigma(n) is not equal to 1.
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1
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2, 3, 4, 5, 7, 8, 9, 12, 13, 18, 19, 22, 27, 29, 32, 36, 37, 43, 45, 48, 49, 50, 61, 64, 67, 68, 72, 73, 75, 80, 81, 82, 91, 98, 100, 101, 104, 106, 109, 116, 121, 122, 128, 129, 133, 134, 137, 144, 146, 148, 149, 152, 156, 157, 160, 162, 163, 169, 171, 173
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OFFSET
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1,1
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COMMENTS
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Apart from 1, all terms of A211656 belong here since the solutions to sigma(x)=sigma(n) form a singleton and thus their GCD is n itself.
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LINKS
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FORMULA
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Numbers such that A241479(n) is not equal to 1.
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PROG
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(PARI) sigv(n) = select(i->sigma(i) == n, vector(n, i, i));
isok(n) = (gcd(sigv(sigma(n))) != 1);
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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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