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 A014957 #23 Jun 12 2024 16:16:48
%S A014957 1,3,5,9,15,21,25,27,39,45,55,63,75,81,105,117,125,135,147,155,165,
%T A014957 171,189,195,205,225,243,273,275,315,333,351,375,405,441,465,495,507,
%U A014957 513,525,567,585,605,609,615,625,657,675,729,735,775,819,825,855,903
%N A014957 Positive integers k that divide 16^k - 1.
%C A014957 Also, positive integers k that divide A014931(k).
%H A014957 Harvey P. Dale, <a href="/A014957/b014957.txt">Table of n, a(n) for n = 1..2000</a>
%t A014957 Join[{1},Select[Range[1000],PowerMod[16,#,#]==1&]] (* _Harvey P. Dale_, Jun 12 2024 *)
%o A014957 (Python)
%o A014957 A014957_list = [n for n in range(1,10**6) if n == 1 or pow(16,n,n) == 1] # _Chai Wah Wu_, Mar 25 2021
%Y A014957 Cf. A067945, A014945, A067946, A014946, A067947, A014949, A068382, A014950, A068383, A014951, A116621, A014956, A177805, A177807, A128358, A128360
%Y A014957 Cf. A128396, A177916
%K A014957 nonn
%O A014957 1,2
%A A014957 _Olivier Gérard_
%E A014957 Edited by _Max Alekseyev_, Sep 10 2011