%I #9 Dec 11 2020 11:29:37
%S 163,643,1651,3379,5203,8371,11059,16291,20803,26275
%N Number of 3 X 3 integer matrices with elements in the range [ -n,n ] which generate a group of order two under binary matrix multiplication.
%F a(n) = 1 + 2*A053171(n).
%Y Cf. A053171.
%K nonn,more
%O 1,1
%A _Ralf W. Grosse-Kunstleve_, Mar 26 2000