This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A276905 #17 Dec 09 2016 09:31:26 %S A276905 12,1452,11352,79398,146520,281622,352110,536778,643302,680988,723492, %T A276905 739200,878988,992112,1115268,1189650,1397022,1698378,1698510,1728540, %U A276905 1806222,2486220,2873178,3031578,3571458,3946140,4467012,4983858,5064510,5135658,5567562,5753352 %N A276905 Numbers k such that k^5-1 and k^5+1 are semiprimes. %t A276905 upper=600000; %t A276905 Select[Range[upper], %t A276905 PrimeOmega[#^5 - 1] == PrimeOmega[#^5 + 1] == 2 &] %o A276905 (PARI) isok(n) = (bigomega(n^5-1)==2) && (bigomega(n^5+1)==2); \\ _Michel Marcus_, Sep 22 2016 %Y A276905 Cf. A001358, A108278, A124936, A268043. %Y A276905 Intersection of A104238 and A261435. %K A276905 nonn %O A276905 1,1 %A A276905 _Gary E. Davis_, Sep 21 2016 %E A276905 More terms from _Altug Alkan_, Sep 30 2016