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 A309672 #22 May 08 2021 08:28:47 %S A309672 2329,4369,10537,35209,281929,1114129,8978569,16843009,143163649, %T A309672 286331153,1086374209,4295098369,9198250129,18325194049,36507844609, %U A309672 73016672273,139055899009,277033877569,586397253889,1103840280833,4673067091009,9382516064513,17868687216769 %N A309672 Composite terms of A007755. %C A309672 10537 is a term because it is composite (= 41*257) and the totient (A000010) iterating "trajectory" starting from 10537 and ending in 1 is longer (length 15) than any similar trajectory starting from a (prime or nonprime) N < 10537. %Y A309672 Cf. A000010, A003434, A049108, A007755, A098196. %K A309672 nonn %O A309672 1,1 %A A309672 _Jeppe Stig Nielsen_, Oct 05 2019