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Search: id:A143012
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| A143012 |
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Numbers of the form (4^p+2^p+1)/7, where p>3 is prime. |
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2
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| 151, 2359, 599479, 9588151, 2454285751, 39268347319, 10052678938039, 41175768098368951, 658812288653553079, 2698495133088002829751, 690814754065816531725751, 11053036065049294753459639
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OFFSET
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1,1
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COMMENT
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If 8^p-1 is squarefree then the terms of the sequence are either primes (A000040) or overpseudoprimes to base 2 (A141232). In particular, composite numbers of the sequence are strong pseudoprimes to base 2 (A001262). E.g. a(5)=2454285751 is A001262(1828).
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REFERENCES
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V. Shevelev, Process of "primoverization" of numbers of the form a^n-1, http:// arxiv.org/abs/0807.2332
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MAPLE
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p:=ithprime: seq((4^p(n)+2^p(n)+1)*1/7, n=3..14); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008]
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CROSSREFS
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Cf. A001262 A141232 A000040 A126614.
Sequence in context: A164622 A139640 A130870 this_sequence A060889 A097640 A038857
Adjacent sequences: A143009 A143010 A143011 this_sequence A143013 A143014 A143015
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KEYWORD
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nonn
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AUTHOR
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Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jul 15 2008, Jul 21 2008
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EXTENSIONS
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Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008
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