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A248796
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Numbers n such that Product_{d|(n-2)} phi(d) = Product_{d|(n-1)} phi(d) where phi(x) = Euler totient function (A000010).
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3
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3, 5, 7, 17, 257, 65537, 2200696, 2619707, 6372796, 40588487, 76466987, 81591196, 118018096, 206569607, 470542487, 525644387, 726638836, 791937616, 971122516, 991172807
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OFFSET
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1,1
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COMMENTS
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The first 5 known Fermat primes (A019434) are terms of this sequence.
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LINKS
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FORMULA
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A029940(a(n)) = a(n)-1 if a(n) = prime.
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EXAMPLE
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PROG
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(Magma) [n: n in [3..100000] | (&*[EulerPhi(d): d in Divisors(n-2)]) eq (&*[EulerPhi(d): d in Divisors(n-1)])]
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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