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 A265498 #17 Sep 08 2022 08:46:14 %S A265498 1,1362,1756,1905,2337,2707,2902,2997,3487,3492,3787,3879,4045,4266, %T A265498 4374,4680,5106,5691,5766,6321,6352,6585,6819,7056,7099,7162,7470, %U A265498 7627,8055,8061,8121,8499,8511,8785,8865,9432,9636,9876,10116,10389,10629,10752,11262 %N A265498 Numbers n such that n*2^521 - 1 is prime. %C A265498 The exponent of 2 in the expression, 521, is a Mersenne exponent. %e A265498 n = 1 is a term since 2^521-1 is prime (13th Mersenne prime). %t A265498 Select[Range@ 12050, PrimeQ[# 2^521 - 1] &] (* _Michael De Vlieger_, Dec 09 2015 *) %o A265498 (MATLAB) %o A265498 if isprime(n*2^521-1) %o A265498 disp(n) %o A265498 end %o A265498 (Magma) [n: n in [1..2*10^4] |IsPrime(n*2^521-1)]; // _Vincenzo Librandi_, Dec 10 2015 %o A265498 (PARI) is(n) = ispseudoprime(n*2^521 - 1); \\ _Altug Alkan_, Dec 10 2015 %Y A265498 Cf. A000043, A001348, A005122. %K A265498 nonn,easy %O A265498 1,2 %A A265498 _Vardan Semerjyan_, Dec 09 2015