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 A139392 #6 Aug 23 2017 02:56:00 %S A139392 9,21,25,27,39,45,49,55,57,63,75,81,93,99,105,111,117,121,125,129,135, %T A139392 147,153,155,165,169,171,175,183,189,195,201,203,205,207,219,225,231, %U A139392 237,243,245,253,261,273,275,279,285,289,291,297,301,305,309,315,325 %N A139392 Odd noncyclic numbers; odd numbers n such that gcd(n,phi(n)) > 1. %C A139392 Sequence A060679 lists all noncyclic numbers, which includes all even numbers >2. %H A139392 T. D. Noe, <a href="/A139392/b139392.txt">Table of n, a(n) for n = 1..1000</a> %t A139392 Select[Range[1,400,2], GCD[ #,EulerPhi[ # ]]>1&] %o A139392 (PARI) is(n)=n%2 && gcd(eulerphi(n),n)>1 \\ _Charles R Greathouse IV_, Aug 23 2017 %Y A139392 Cf. A003277 (cyclic numbers). %K A139392 nonn %O A139392 1,1 %A A139392 _T. D. Noe_, Apr 17 2008