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%I #14 Dec 03 2020 20:55:43
%S 1,2,1,3,2,3,1,2,1,4,1,2,4,3,2,3,1,5,3,4,3,6,1,3,1,3,1,5,2,3,3,2,2,4,
%T 1,2,4,5,2,5,2,4,4,3,3,6,2,2,3,3,1,3,2,5,3,2,1,6,1,2,3,3,2,4,1,3,3,8,
%U 4,6,3,3,4,4,2,4,2,5,1,3,1,6,2,2,3,4,2,5,2,3,5,3,4,6,3,2,3,5,1,4,2,5,6,2,1,4,2,4,5,5,2,6,4,4,4,5,5,7
%N a(n) is the smallest k such that the first k primes generate the multiplicative group modulo n.
%H H. Brown and H. Zassenhaus, <a href="http://dx.doi.org/10.1016/0022-314X(71)90004-7">Some empirical observations on primitive roots</a>, J. Number Theory 3 (1971) 306-309.
%H S. R. Finch, <a href="/A232927/a232927.pdf">Average least nonresidues</a>, December 4, 2013. [Cached copy, with permission of the author]
%H P. Pollack, <a href="http://dx.doi.org/10.1016/j.jnt.2011.12.015">The average least quadratic nonresidue modulo m and other variations on a theme of Erdos</a>, J. Number Theory 132 (2012) 1185-1202.
%Y Cf. A098990, A249270.
%K nonn
%O 3,2
%A _Steven Finch_, Dec 02 2013