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1, 2, 2, 3, 3, 5, 5, 9, 3, 9, 7, 15, 11, 11, 5, 7, 13, 25, 17, 21, 9, 35, 19, 45, 5, 121, 9, 49, 23, 25, 29, 81, 11, 385, 7, 21, 31, 23, 35, 49, 37, 55, 41, 39, 15, 1105, 43, 135, 7, 35, 121, 51, 47, 125, 25, 99, 385, 4693, 53, 105, 59, 85085, 21, 55, 13, 175, 61, 5929, 23, 77, 67, 77, 71, 279841, 25, 8281, 11, 1225
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OFFSET
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1,2
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LINKS
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FORMULA
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PROG
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(PARI)
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
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};
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CROSSREFS
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Cf. also A332223 (sigma similarly conjugated).
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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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