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A275159
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Primes p such that p-1 is the value of totient function of a product of distinct Fermat numbers (A000215).
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0
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2, 3, 5, 17, 257, 65537, 548898078721, 1151122703583805441, 77370970260794891965562881, 632834090662785970268956262401, 1327149278901642923121482163604684801, 2787593149816327845958662202634335514787841, 91343852333181430856373443055921906148567941121
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OFFSET
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1,1
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COMMENTS
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Primes p such that p-1 = phi(A001317(x)) has solution.
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LINKS
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EXAMPLE
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Prime 548898078721 is in the sequence because 548898078720 = phi(1095216660735) = phi(3*5*17*4294967297); all numbers 3, 5, 17 and 4294967297 are terms of A000215 (Fermat numbers).
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PROG
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(Magma) Set(Sort([EulerPhi(k)+1: k in [A001317(n)] | IsPrime(EulerPhi(k)+1)]))
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CROSSREFS
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Supersequence of A019434 (Fermat primes) and A092506 (primes of the form 2^n+1).
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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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