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A107654
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Numbers n such that if sum of the proper divisors of n is equal to m then n=phi(m).
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0
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OFFSET
| 1,1
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COMMENTS
| Next term is greater than 65*10^6.
4*10^9 < a(8) <= 46367354880. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 12 2008]
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EXAMPLE
| 62000640 is in the sequence because sigma(62000640)-62000640=187545888 and phi(187545888)=62000640.
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MATHEMATICA
| Do[If[n == EulerPhi[DivisorSigma[1, n]-n], Print[n]], {n, 65000000}]
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CROSSREFS
| Cf. A107653.
Sequence in context: A003134 A191303 A186849 * A015359 A201268 A200658
Adjacent sequences: A107651 A107652 A107653 * A107655 A107656 A107657
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KEYWORD
| more,nonn
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AUTHOR
| Farideh Firoozbakht (mymontain(AT)yahoo.com), May 26 2005
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EXTENSIONS
| a(7) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 12 2008
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