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A056006
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Numbers n such that n | Sigma(n) + 2.
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2
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OFFSET
| 1,2
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COMMENTS
| n | Sigma(n) gives the multi-perfect numbers A007691, n | Sigma(n) +1 if n is a power of 2 A000079.
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MATHEMATICA
| Do[If[Mod[DivisorSigma[1, n]+2, n]==0, Print[n]], {n, 1, 7*10^8}]
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PROG
| (PARI) for(n=1, 5e9, if((sigma(n)+2)%n==0, print1(n", "))) \\ Charles R Greathouse IV, Jun 01 2011
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CROSSREFS
| Cf. A045768.
Sequence in context: A173415 A199232 * A191363 A067999 A156193 A119035
Adjacent sequences: A056003 A056004 A056005 * A056007 A056008 A056009
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KEYWORD
| nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 24 2000
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EXTENSIONS
| a(6) from Charles R Greathouse IV, Jun 01 2011
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