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 A128895 #13 Jul 12 2018 08:52:56 %S A128895 1,5,17,17,17,227,227,5297,5297,5297,226817,1227497,2270483,5967617, %T A128895 8617187,27311693,39928787,39928787,345664343,345664343 %N A128895 Least positive primitive root that all of the first n primes share. %H A128895 Don Reble, <a href="/A128895/b128895.txt">Table of n, a(n) for n = 1..37</a> %e A128895 A primitive root of 2 must be == 1 (mod 2); for 3, it must be == 2 (mod 3), and for 5 it must be == 2 or 3 (mod 5). The smallest such number is 17, so a(3)=17. %Y A128895 Cf. A001918, A060749. %K A128895 nonn %O A128895 1,2 %A A128895 _Martin Raab_, Apr 20 2007