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A063943
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Numbers n such that phi(n) = sigma(n) - sigma(n+1).
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1
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170, 518, 15416, 16472, 21584, 52744, 140864, 187736, 196318, 318626, 354118, 639286, 828814, 942326, 1333172, 1604018, 3301024, 5240458, 6490678, 7552264, 8040166, 8321326, 9790430, 12237950, 12461834, 14818438, 19012455, 20392318, 22625158, 29201984
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OFFSET
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1,1
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LINKS
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PROG
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(PARI) for(n=1, 30000000, if(eulerphi(n)==sigma(n)-sigma(n+1), print1(n, ", ")))
(PARI) { n=-1; t=0; for (m=1, 10^9, s=t; t=sigma(m + 1); if (eulerphi(m)==s - t, write("b063943.txt", n++, " ", m); if (n==38, break)) ) } [Harry J. Smith, Sep 03 2009]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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