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 A250189 #12 May 21 2018 03:22:46
%S A250189 2,3,4,31,37,39,46,77,98,119,124,143,144,154,169,197,205,232,245,266,
%T A250189 291,295,297,305,308,319,332,333,413,426,431,437,454,459,472,483,513,
%U A250189 528,531,542,579,617,619,635,647,677,724,737,748,780,806,815,819,820,840,851,858,870,875,907,920,927,940,983,1002,1028
%N A250189 Numbers n such that Phi(40,n) is prime, where Phi is the cyclotomic polynomial.
%H A250189 G. C. Greubel, <a href="/A250189/b250189.txt">Table of n, a(n) for n = 1..10000</a>
%t A250189 Select[Range[1200], PrimeQ[Cyclotomic[40, #]] &] (* _Vincenzo Librandi_, Jan 16 2015 *)
%o A250189 (PARI) {is(n)=isprime(polcyclo(40,n))};
%o A250189 for(n=1,1000, if(is(n), print1(n, ", "))) \\ _G. C. Greubel_, May 20 2018
%Y A250189 Cf. A246392.
%K A250189 nonn
%O A250189 1,1
%A A250189 _R. J. Mathar_, Jan 12 2015