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 A240099 #10 Mar 18 2015 11:05:36 %S A240099 1,44250,1004004,3490575,3517335,5750115,10729026,19193559,20251770, %T A240099 25284039,25552194,30204801,33733206,39015405,47518809,52463445, %U A240099 58370025,69502971,72009429,77086380,78510156,83972646,85955475,89190969,90499584,92246199,95374005 %N A240099 Integers n such that 2n^k + 1, for k = 2..6, are prime. %C A240099 Note that 2n^7+1 may or may not be prime. %C A240099 First n>1 such that 2n^k+1, for k=2..7, are prime, is a(4) = 3490575. %C A240099 First n>1 such that 2n^k+1, for k=2..8, are prime, is 83972646. %C A240099 Subsequence of A239925: a(2) = 44250 = A239925(4), a(3) = 1004004 = A239925(27). %t A240099 Select[Range[10^8],AllTrue[2#^Range[2,6]+1,PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Mar 18 2015 *) %Y A240099 Cf. A089001, A168550, A239874, A239925. %K A240099 nonn %O A240099 1,2 %A A240099 _Zak Seidov_, Apr 01 2014