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A281576
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Composite Fermat numbers.
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4
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OFFSET
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1,1
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COMMENTS
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Fermat numbers F_i such that A152155(i) != -1, where i is the index of F in A000215.
Is this sequence infinite?
All the terms are Fermat pseudoprimes to base 2 (A001567). For a proof see, e.g., Jaroma and Reddy (2007). - Amiram Eldar, Jul 24 2021
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LINKS
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PROG
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(PARI) a152155(n) = centerlift(Mod(3, 2^(2^n)+1)^(2^(2^n-1)))
terms(n) = my(i=0, k=1); while(1, if(a152155(k)!=-1, print1(2^(2^k)+1, ", "); i++); if(i==n, break); k++)
terms(4) \\ print initial 4 terms
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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