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 A087268 #16 Jun 04 2025 10:24:15
%S A087268 1,2,3,5,7,9,11,12,13,17,18,19,21,23,25,26,28,29,31,32,34,35,36,37,41,
%T A087268 42,43,45,47,49,52,53,55,57,59,60,61,65,67,68,69,70,71,73,74,76,79,81,
%U A087268 83,84,85,86,87,88,89,91,95,97,98,99,101,103,104,106,107,109,110,111
%N A087268 Solutions to gcd(x, pi(x)) = 1, where pi is A000720.
%H A087268 Ivan Neretin, <a href="/A087268/b087268.txt">Table of n, a(n) for n = 1..10000</a>
%e A087268 All primes are included.
%t A087268 Flatten[Position[Table[GCD[w, PrimePi[w]], {w, 1, 256}], 1]]
%o A087268 (PARI) isok(n) = gcd(n, primepi(n)) == 1; \\ _Michel Marcus_, Apr 22 2018
%Y A087268 Cf. A007053, A000720, A087266, A087267, A057809.
%K A087268 nonn
%O A087268 1,2
%A A087268 _Labos Elemer_, Sep 16 2003