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Search: id:A088826
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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
1
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OFFSET
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1,1
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COMMENT
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a(7) > 10^10. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Sep 30 2009]
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EXAMPLE
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n=1242, sigma[1242]=2880, 2880-2484=396=phi[1242].
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MATHEMATICA
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Do[If[Equal[DivisorSigma[1, n]-2*n, EulerPhi[n]], Print[n]], {n, 1, 10000000}]
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CROSSREFS
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Cf. A000203, A000010, A077374, A033880.
Sequence in context: A007586 A122973 A074356 this_sequence A125221 A082829 A003357
Adjacent sequences: A088823 A088824 A088825 this_sequence A088827 A088828 A088829
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KEYWORD
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more,nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Oct 27 2003
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EXTENSIONS
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a(5)-a(6) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Sep 30 2009
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