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A092873
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Prime factors of the odd terms of A007755.
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3
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3, 5, 11, 17, 41, 83, 137, 257, 641, 1097, 17477, 65537, 140417, 557057, 2384897, 4227137, 35946497, 71304257, 541073537, 2281701377, 2336497860617, 600470787982337, 2278291849363457, 4538923050090497, 38280596832649217
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Catlin shows that if A007755(n) is odd and composite, then its factors are among the A007755(k), k < n. Note that the five Fermat primes are in this sequence.
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REFERENCES
| P. A. Catlin, Concerning the iterated phi function, Amer. Math. Monthly, Vol. 77, No. 1 (1970), 60-61.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..288 (odd primes in the first 1000 terms of A007755)
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CROSSREFS
| Sequence in context: A096479 A129809 A040176 * A158641 A019386 A154622
Adjacent sequences: A092870 A092871 A092872 * A092874 A092875 A092876
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KEYWORD
| nonn
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AUTHOR
| T. D. Noe (noe(AT)sspectra.com), Mar 08 2004
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EXTENSIONS
| More terms from T. D. Noe (noe(AT)sspectra.com), Aug 03 2005
a(21) corrected and comment deleted. - T. D. Noe (noe(AT)sspectra.com), Nov 18 2008
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