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 A082495 #18 Dec 01 2022 10:50:07
%S A082495 0,1,1,3,1,3,1,7,7,3,1,3,1,3,7,15,1,9,1,15,7,3,1,15,6,3,25,15,1,3,1,
%T A082495 31,7,3,17,27,1,3,7,15,1,21,1,15,16,3,1,15,29,23,7,15,1,27,42,31,7,3,
%U A082495 1,15,1,3,7,63,31,63,1,15,7,43,1,63,1,3,67,15,17,63,1,15,79,3,1,63,31,3,7,79
%N A082495 a(n) = (2^n - 1) mod n.
%H A082495 Reinhard Zumkeller, <a href="/A082495/b082495.txt">Table of n, a(n) for n = 1..10000</a>
%F A082495 a(n) = A015910(n) + A048298(n) - 1.
%t A082495 Table[Mod[2^m-1,m],{m,6!}] (* _Vladimir Joseph Stephan Orlovsky_, Feb 11 2010 *)
%o A082495 (PARI) vector(80, n, (2^n-1) %n) \\ _Michel Marcus_, Jan 16 2015
%o A082495 (Haskell)
%o A082495 a082495 n = a015910 n + a048298 n - 1 -- _Reinhard Zumkeller_, Oct 17 2015
%o A082495 (Python)
%o A082495 def A082495(n): return (m if (m:=pow(2,n,n)) else n)-1 # _Chai Wah Wu_, Dec 01 2022
%Y A082495 Cf. A015910, A048298.
%Y A082495 Cf. A000079, A062173.
%K A082495 easy,nonn
%O A082495 1,4
%A A082495 Anonymous, Apr 28 2003