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 A156585 #16 Apr 08 2018 03:24:35 %S A156585 2,3,7,59 %N A156585 Numbers such that (2^(n^2)-1)/(2^n-1) is prime. %C A156585 It is easy to see that all terms of this sequence must be prime; this motivates the definition of A051156(n) = (2^prime(n)^2-1)/(2^prime(n)-1). %C A156585 No further terms up to n=1999. - _Andreas Höglund_, Apr 06 2018 %t A156585 Select[Prime[Range[17]], PrimeQ[Cyclotomic[#^2, 2]] &] (* _Arkadiusz Wesolowski_, May 13 2012 *) %o A156585 (PARI) for/*prime*/( n=1,99, is/*pseudo*/prime( (2^n^2-1)/(2^n-1) ) & print1(n,",")) %Y A156585 Cf. A051156. %K A156585 hard,more,nonn %O A156585 1,1 %A A156585 _M. F. Hasler_, Feb 10 2009