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1, 1, 5, 1, 3, 11, 17, 1, 1, 19, 11, 23, 65, 35, 7, 1, 43, 9, 257, 13, 37, 67, 171, 47, 25, 131, 29, 71, 205, 43, 2049, 1, 23, 259, 41, 55, 4097, 103, 19, 79, 2731, 25, 16385, 45, 15, 1027, 10923, 95, 49, 17, 29, 263, 65537, 59, 73, 143, 517, 2051, 43691, 29, 262145, 4099, 77, 1, 137, 139, 524289, 173, 343, 83
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OFFSET
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1,3
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COMMENTS
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Denominator of ratio sigma(n) / A156552(2*n).
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LINKS
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FORMULA
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PROG
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(PARI)
A156552(n) = {my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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