%I #6 Dec 02 2017 20:50:54
%S 1863,1971,4292,7624,8180,15140,17875,19524,20180,21020,23732,23751,
%T 28371,30124,33032,33939,34532,35427,36620,40071,41444,42579,44739,
%U 45128,45603,46052
%N Numbers n such that there are precisely 15 groups of orders n and n + 1.
%C Equivalently, lower member of consecutive terms of A294156.
%H H. U. Besche, B. Eick and E. A. O'Brien. <a href="http://dx.doi.org/10.1142/S0218196702001115">A Millennium Project: Constructing Small Groups</a>, Internat. J. Algebra and Computation, 12 (2002), 623-644.
%H Gordon Royle, <a href="http://staffhome.ecm.uwa.edu.au/~00013890/remote/cubcay/">Numbers of Small Groups</a>
%H <a href="/index/Gre#groups">Index entries for sequences related to groups</a>
%F Sequence is { n | A000001(n) = 15, A000001(n+1) = 15 }.
%e 1863 is in the sequence because A000001(1863) = A000001(1864) = 15, 1971 is in the sequence because A000001(1971) = A000001(1972) = 15 and 19524 is in the sequence because A000001(19524) = A000001(19525) = 15.
%Y Cf. A000001, A294156.
%K nonn
%O 1,1
%A _Muniru A Asiru_, Dec 02 2017