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 A067241 #15 May 01 2025 08:24:10 %S A067241 3,5,8,9,21,23,33,39,51,63,65,81,89,95,99,113,131,173,183,191,209,215, %T A067241 221,239,245,251,261,281,285,299,303,309,315,341,345,363,369,371,393, %U A067241 411,419,431,443,473,495,509,525,543,545,561,575,593,645,659,683,711 %N A067241 Numbers k such that gcd((2*k)!+1, k!+1) > 1. %H A067241 Amiram Eldar, <a href="/A067241/b067241.txt">Table of n, a(n) for n = 1..10000</a> %t A067241 q[k_] := !CoprimeQ[(2*k)!+1, k!+1]; Select[Range[720], q] (* _Amiram Eldar_, May 01 2025 *) %o A067241 (PARI) isok(k) = gcd((2*k)!+1, k!+1) > 1; \\ _Amiram Eldar_, May 01 2025 %Y A067241 Cf. A038507, A127231. %K A067241 easy,nonn %O A067241 1,1 %A A067241 _Benoit Cloitre_, Feb 20 2002