%I #14 May 15 2016 03:52:02
%S 0,0,1,3,7,22,89,779,30078,8785772,48803495722,1774274116992170
%N Number of exponent-2 class 2 groups of order 2^n.
%H J. H. Conway, Heiko Dietrich and E. A. O'Brien, <a href="http://www.math.auckland.ac.nz/~obrien/research/gnu.pdf">Counting groups: gnus, moas and other exotica</a>, The Mathematical Intelligencer, March 2008, Volume 30, Issue 2, pp 6-15.
%H Bettina Eick and E. A. O'Brien, <a href="http://www.math.auckland.ac.nz/~obrien/research/count-pgroups.pdf">Enumerating p-groups</a>. Group theory. J. Austral. Math. Soc. Ser. A 67 (1999), no. 2, 191-205.
%H E. A. O'Brien, <a href="https://www.math.auckland.ac.nz/~obrien/research/bibliography.pdf">Bibliography on the determination of finite groups</a>.
%Y Cf. A000679, A252785, A252786, A252787.
%K nonn,hard,more
%O 0,4
%A _Eric M. Schmidt_, Dec 21 2014