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 A276905 Numbers k such that k^5-1 and k^5+1 are semiprimes. 1
 12, 1452, 11352, 79398, 146520, 281622, 352110, 536778, 643302, 680988, 723492, 739200, 878988, 992112, 1115268, 1189650, 1397022, 1698378, 1698510, 1728540, 1806222, 2486220, 2873178, 3031578, 3571458, 3946140, 4467012, 4983858, 5064510, 5135658, 5567562, 5753352 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS MATHEMATICA upper=600000; Select[Range[upper], PrimeOmega[#^5 - 1] == PrimeOmega[#^5 + 1] == 2 &] PROG (PARI) isok(n) = (bigomega(n^5-1)==2) && (bigomega(n^5+1)==2); \\ Michel Marcus, Sep 22 2016 CROSSREFS Cf. A001358, A108278, A124936, A268043. Intersection of A104238 and A261435. Sequence in context: A181856 A161149 A160490 * A015096 A271434 A299694 Adjacent sequences:  A276902 A276903 A276904 * A276906 A276907 A276908 KEYWORD nonn AUTHOR Gary E. Davis, Sep 21 2016 EXTENSIONS More terms from Altug Alkan, Sep 30 2016 STATUS approved

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Last modified September 25 09:26 EDT 2020. Contains 337335 sequences. (Running on oeis4.)