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 A004649 #25 Oct 26 2023 08:33:21
%S A004649 0,1,1,3,3,5,5,7,2,1,4,5,4,5,8,11,10,13,14,13,16,17,20,1,1,25,26,25,
%T A004649 26,7,7,9,7,13,11,13,15,15,17,19,17,23,21,21,19,27,35,35,33,33,35,33,
%U A004649 39,41,43,45,43,45,45,43,49,59,59,57,57,1,2,7,4,3,4,7,8
%N A004649 a(n) = prime(n) mod (n-1).
%H A004649 Vincenzo Librandi, <a href="/A004649/b004649.txt">Table of n, a(n) for n = 2..1000</a>
%t A004649 Table[Mod[Prime[n], n - 1], {n, 2, 100}] (* _Vincenzo Librandi_, Sep 11 2014 *)
%o A004649 (PARI) a(n) = prime(n) % (n-1) \\ _Michel Marcus_, Jun 12 2013
%o A004649 (Magma) [NthPrime(n) mod (n-1): n in [2..90]]; // _Vincenzo Librandi_, Sep 11 2014
%Y A004649 Cf. A004648, A004650.
%K A004649 nonn,easy
%O A004649 2,4
%A A004649 _N. J. A. Sloane_, Daniel Wild (wild(AT)edumath.u-strasbg.fr)