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 A200906 #21 Jun 20 2015 14:42:37
%S A200906 0,1,2,4,5,21,44,64,244,268,2415
%N A200906 Numbers n such that cyclotomic polynomial value Phi(5,n!) is prime.
%C A200906 2415 corresponds to a probable prime. - _Serge Batalov_, Nov 24 2011
%C A200906 a(12) > 15000. - _Robert Price_, Jun 20 2015
%e A200906 5 is in the sequence because Phi(5,5!) = ((5!)^5-1)/(5!-1)= 209102521 is prime.
%t A200906 Do[If[PrimeQ[Cyclotomic[5, n!]], Print[n]], {n, 0, 600}]
%o A200906 (PARI) for(n=0,600,x=n!;if(isprime(eval(polcyclo(5))),print(n)))
%Y A200906 Cf. A002981, A002982, A046029, A046029.
%K A200906 nonn
%O A200906 1,3
%A A200906 _Serge Batalov_, Nov 23 2011