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A088826
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Solutions to sigma[n]-2n=phi[n]: abundance of n equals Euler-phi of n.
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0
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OFFSET
| 1,1
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COMMENTS
| a(7) > 10^10. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Sep 30 2009]
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EXAMPLE
| n=1242, sigma[1242]=2880, 2880-2484=396=phi[1242].
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MATHEMATICA
| Do[If[Equal[DivisorSigma[1, n]-2*n, EulerPhi[n]], Print[n]], {n, 1, 10000000}]
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CROSSREFS
| Cf. A000203, A000010, A077374, A033880.
Sequence in context: A122973 A074356 A172294 * A125221 A082829 A003357
Adjacent sequences: A088823 A088824 A088825 * A088827 A088828 A088829
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KEYWORD
| more,nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Oct 27 2003
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EXTENSIONS
| a(5)-a(6) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Sep 30 2009
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