A276905 Numbers k such that k^5-1 and k^5+1 are semiprimes.

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

Offset: 1

Author

Gary E. Davis, Sep 21 2016

Keywords

• nonn

Crossrefs

Cf. A001358, A108278, A124936, A268043.

Intersection of A104238 and A261435.

Programs

Mathematica

upper=600000;
Select[Range[upper],
PrimeOmega[#^5 - 1] == PrimeOmega[#^5 + 1] == 2 &]

PARI

isok(n) = (bigomega(n^5-1)==2) && (bigomega(n^5+1)==2); \\ Michel Marcus, Sep 22 2016

Extensions

More terms from Altug Alkan, Sep 30 2016