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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

Table of n, a(n) for n=1..32.

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.)