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 A068483 #11 Oct 16 2018 20:09:29 %S A068483 11,15,35,75,83,111,119,135,155,179,219,231,243,323,359,375,455,459, %T A068483 483,491,515,519,525,531,551,611,615,639,651,663,699,719,723,735,771, %U A068483 779,783,803,879,915,923,939,999,1043,1103,1119,1175,1199,1271,1323 %N A068483 Numbers n such that gcd(n!-1,2^n-1)>1. %H A068483 G. C. Greubel, <a href="/A068483/b068483.txt">Table of n, a(n) for n = 1..1000</a> %t A068483 Select[Range[2500], GCD[#! - 1, 2^# - 1] > 1 &] (* _G. C. Greubel_, Oct 15 2018 *) %o A068483 (PARI) isok(n) = gcd(n!-1,2^n-1) > 1; \\ _Michel Marcus_, Oct 16 2018 %Y A068483 Cf. A000225 (2^n-1), A033312 (n!-1). %Y A068483 Cf. A068480, A068481, A068482. %K A068483 easy,nonn %O A068483 1,1 %A A068483 _Benoit Cloitre_, Mar 10 2002