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 A265505 #12 Jan 18 2016 09:59:09 %S A265505 1,25,36,81,246,273,358,378,595,658,684,703,706,739,759,883,909,958, %T A265505 963,970,991,1014,1054,1138,1189,1200,1209,1356,1359,1476,1488,1534, %U A265505 1554,1590,1594,1684,1695,1719,1785,1791,1858,1929,2008,2094,2103,2115,2146,2224,2229,2266,2278,2283,2313,2325,2380,2388,2401 %N A265505 Numbers n such that n*2^107 - 1 is prime. %C A265505 The exponent of 2 in the expression, 107, is a Mersenne exponent. %e A265505 n = 1 is a term since 2^107 - 1 is prime (the 11th Mersenne prime). %t A265505 Select[Range@ 2401, PrimeQ[# 2^107 - 1] &] (* _Michael De Vlieger_, Dec 16 2015 *) %o A265505 (MATLAB) %o A265505 if isprime(n*2^107-1) %o A265505 disp(n) %o A265505 end %o A265505 (PARI) is(n)=ispseudoprime(n*2^107- 1) \\ _Anders Hellström_, Dec 16 2015 %Y A265505 Cf. A000043, A001348, A005122, A265497, A265502, A265503, A265504. %K A265505 nonn %O A265505 1,2 %A A265505 _Vardan Semerjyan_, Dec 09 2015