%I #12 Mar 06 2020 03:18:39
%S 1,2,9,74,1740,149572,48575680,56147642904,229149201466592,
%T 3333310913116926416,174695272793893644765312,
%U 33301710992572083379669646560,23278728241293538748514513208527104
%N Number of nonisomorphic and nonantiisomorphic relations.
%F a(n) = (A000595(n) + A002500(n)) / 2. - _Sean A. Irvine_, Mar 05 2020
%Y Cf. A000595, A002500.
%K nonn,nice
%O 0,2
%A _Christian G. Bower_, Jan 15 1998 and Jun 15 1998