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 A072190 #19 May 08 2018 15:11:55 %S A072190 2,3,5,6,8,10,12,16,17,18,19,23,26,28,32,34,35,38,40,41,42,45,47,49, %T A072190 57,62,66,69,70,74,75,77,81,82,86,89,91,94,97,99,100,101,102,103,107, %U A072190 112,114,119,120,121,123,126,127,134,137,138,139,142,144,145,147 %N A072190 Indices of primes with primitive root 2. %C A072190 Artin conjectured that this sequence is infinite (this is the famous Artin Conjecture). %D A072190 M. Abramowitz and I.A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 864 %D A072190 J. H. Conway and R. K. Guy, The Book of Numbers, Copernicus Press, New York, 1996. see p. 169 %D A072190 L. Huber, manuscripts on Group Theory and Number Theory, 1990-1995 %H A072190 T. D. Noe, <a href="/A072190/b072190.txt">Table of n, a(n) for n = 1..1000</a> %H A072190 M. Abramowitz and I. A. Stegun, eds., <a href="http://www.convertit.com/Go/ConvertIt/Reference/AMS55.ASP">Handbook of Mathematical Functions</a>, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]. %H A072190 <a href="/index/Ar#Artin">Index entries for sequences related to Artin's conjecture</a> %e A072190 8 is an element of the sequence: 19 the 8th prime and 2 is primitive root of 19. 9 is not element of the sequence, since 23 is the 9th prime and 2 is not primitive root of 23. %t A072190 Select[Range[300], MultiplicativeOrder[2, Prime[#]] == Prime[#] - 1 &] (* _T. D. Noe_, Apr 16 2014 *) %Y A072190 Cf. A001122, A001123, A001124, A001125. %K A072190 easy,nonn %O A072190 1,1 %A A072190 _Miklos Kristof_, Jul 02 2002 %E A072190 Edited by _N. J. A. Sloane_, Apr 11 2009 %E A072190 Extended by _T. D. Noe_, Apr 16 2014