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 A125874 #10 Aug 02 2025 12:13:29
%S A125874 1,3,4,9,15,16,18,21,28,30,33,40,45,60,64,66,81,96,99,105,108,121,135,
%T A125874 144,150,154,165,168,175,189,198,210,225,240,243,250,288,294,324,336,
%U A125874 343,378,396,420,448,450,490,495,525,528,550,616,625,640,675,700,726
%N A125874 Numbers k such that p=22*k+1 is prime and cos(2*Pi/p) is an algebraic number of an 11-smooth degree, but not 7-smooth.
%C A125874 Numbers k such that p=22*k+1 is prime and the greatest prime divisor of p-1 is 11.
%t A125874 Do[If[Take[FactorInteger[EulerPhi[22n+1]][[ -1]],1]=={11} && PrimeQ[22n+1],Print[n]],{n,1,10000}]
%Y A125874 Cf. A125866-A125878.
%K A125874 nonn
%O A125874 1,2
%A A125874 _Artur Jasinski_, Dec 13 2006
%E A125874 Edited by _Don Reble_, Apr 24 2007