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 A250180 #12 May 21 2018 03:24:48 %S A250180 1,22,33,39,43,62,74,134,142,167,212,238,287,313,335,369,414,415,418, %T A250180 432,509,604,679,697,770,782,815,859,874,895,897,924,1039,1048,1070, %U A250180 1085,1134,1145,1170,1177,1212,1239,1240,1262,1339,1347,1364,1374,1407,1413,1414,1449 %N A250180 Numbers n such that Phi_25(n) is prime, where Phi is the cyclotomic polynomial. %H A250180 G. C. Greubel, <a href="/A250180/b250180.txt">Table of n, a(n) for n = 1..10000</a> %t A250180 a250180[n_] := Select[Range[n], PrimeQ@Cyclotomic[25, #] &]; a250180[256] %o A250180 (PARI) isok(n) = isprime(polcyclo(25, n)); \\ _Michel Marcus_, Dec 27 2014 %Y A250180 See A250177 for references. %K A250180 nonn %O A250180 1,2 %A A250180 _Eric Chen_, Dec 26 2014