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A259184
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a(n) = 1 - sigma(n) + sigma(n)^2.
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3
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1, 7, 13, 43, 31, 133, 57, 211, 157, 307, 133, 757, 183, 553, 553, 931, 307, 1483, 381, 1723, 993, 1261, 553, 3541, 931, 1723, 1561, 3081, 871, 5113, 993, 3907, 2257, 2863, 2257, 8191, 1407, 3541, 3081, 8011, 1723, 9121, 1893, 6973, 6007, 5113, 2257, 15253
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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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MAPLE
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MATHEMATICA
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Table[1 - DivisorSigma[1, n] + DivisorSigma[1, n]^2, {n, 10000}]
Table[Cyclotomic[6, DivisorSigma[1, n]], {n, 10000}]
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PROG
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(PARI) a(n) = polcyclo(6, sigma(n)); \\ Michel Marcus, Jun 25 2015
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CROSSREFS
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Cf. A000203 (sum of divisors of n).
Cf. A259185 (indices of primes in this sequence), A259186 (corresponding primes).
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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