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 A083528 #38 Sep 08 2022 08:45:10
%S A083528 1,1,5,1,5,1,5,1,17,5,5,1,5,25,5,1,5,1,5,25,41,25,5,1,25,25,53,9,5,25,
%T A083528 5,1,59,25,45,1,5,25,47,65,5,1,5,9,35,25,5,1,19,25,23,1,5,1,45,81,11,
%U A083528 25,5,25,5,25,125,1,5,49,5,81,125,65,5,1,5,25,125,17,3,25,5,65,161,25,5,1,65
%N A083528 a(n) = 5^n mod 2*n.
%C A083528 a(n) = 1 iff n is in A067946. - _Robert Israel_, Dec 26 2014
%H A083528 Vincenzo Librandi, <a href="/A083528/b083528.txt">Table of n, a(n) for n = 1..1000</a>
%e A083528 a(3) = 5 because 5^3 = 125 and 125 == 5 mod (2 * 3).
%e A083528 a(4) = 1 because 5^4 = 625 and 625 == 1 mod (2 * 4).
%p A083528 seq(5 &^n mod (2*n), n = 1 .. 100); # _Robert Israel_, Dec 26 2014
%t A083528 Table[PowerMod[5, w, 2w], {w, 1, 100}]
%o A083528 (PARI) vector(100, n, lift(Mod(5, 2*n)^n)) \\ _Michel Marcus_, Dec 29 2014
%o A083528 (Magma) [Modexp(5, n, 2*n): n in [1..80]]; // _Vincenzo Librandi_, Oct 19 2018
%Y A083528 Cf. A000079, A000244, A000351, A000420, A082511.
%Y A083528 Cf. A067946, A083529, A083530.
%K A083528 easy,nonn
%O A083528 1,3
%A A083528 _Labos Elemer_, Apr 30 2003