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A008332
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Sum of divisors of p-1, p prime.
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4
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1, 3, 7, 12, 18, 28, 31, 39, 36, 56, 72, 91, 90, 96, 72, 98, 90, 168, 144, 144, 195, 168, 126, 180, 252, 217, 216, 162, 280, 248, 312, 252, 270, 288, 266, 372, 392, 363, 252, 308, 270, 546, 360, 508, 399, 468, 576, 456, 342, 560, 450, 432, 744, 468, 511, 396, 476, 720, 672
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OFFSET
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1,2
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COMMENTS
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REFERENCES
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Yu. V. Linnik. The dispersion method in binary additive problems, Izdat. Leningrad Univ., Leningrad, 1961.
József Sándor, Dragoslav S. Mitrinovic and Borislav Crstici, Handbook of Number Theory I, Springer Science & Business Media, 2005, Chapter III, p. 87.
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LINKS
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FORMULA
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Sum_{k=1..n} a(k) ~ (zeta(2)*zeta(3)/zeta(6)) * n + O(n/log(n)^0.999) (Linnik, 1961). - Amiram Eldar, Mar 04 2021
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MAPLE
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for i from 1 to 500 do if isprime(i) then print(sigma(i-1)); fi; od;
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MATHEMATICA
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PROG
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(Magma) [DivisorSigma(1, NthPrime(n)-1): n in [1..60]]; // Vincenzo Librandi, Aug 20 2018
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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