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 A129495 #10 Jul 24 2021 05:40:23 %S A129495 10,15,20,26,30,34,38,40,46,50,56,58,60,62,65,74,78,82,86,94,100,106, %T A129495 118,120,122,124,129,130,132,134,140,141,142,143,146,150,155,158,159, %U A129495 166,177,178,182,183,190,194,195,200,201,202,206,213,214,217,218,219 %N A129495 Composite numbers k such that 5^k (mod k) is a power of 5 greater than 1. %H A129495 Amiram Eldar, <a href="/A129495/b129495.txt">Table of n, a(n) for n = 1..10000</a> %e A129495 26 is a member of the sequence since 5^26 (mod 26) == 25. %t A129495 Select[Range@ 225, (p = PowerMod[5, #, #]) > 1 && IntegerQ@ Log[5, p] && CompositeQ[#] &] (* corrected by _Amiram Eldar_, Jul 24 2021 *) %Y A129495 Cf. A036236, A129492, A129493, A129494, A129496, A129497. %K A129495 easy,nonn %O A129495 1,1 %A A129495 _Robert G. Wilson v_, Apr 17 2007