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A006596
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Numbers k such that (2^(2k+1) - 2^(k+1) + 1)/5 is prime.
(Formerly M1325)
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0
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2, 5, 6, 14, 21, 26, 141, 278, 281, 306, 345, 1365, 2573, 2661, 4766, 5385
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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REFERENCES
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J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
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MATHEMATICA
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For[ i=1, i<=10000, i++, If[ PrimeQ[ ( 2^(2n+1) - 2^(n+1) + 1)/5 ], Print[ n ] ] ]
Select[Range[5400], PrimeQ[(2^(2#+1)-2^(#+1)+1)/5]&] (* Harvey P. Dale, Jun 28 2023 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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More terms from Douglas R. Burke (dburke(AT)nevada.edu)
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STATUS
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approved
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