%I #8 Aug 22 2024 17:10:36
%S 1,1,3,5,12,24,58,128,309,717,1731,4109,9920,23780,57410,138192,
%T 333625,804457,1942131,4686341,11313828,27308256,65927962,159150320,
%U 384222861,927562581,2239334163,5406150125,13051600952,31509157004
%N Number of nonisomorphic and nonantiisomorphic reflexive transitive and cotransitive (complement is transitive) relations.
%H Michael De Vlieger, <a href="/A030270/b030270.txt">Table of n, a(n) for n = 0..2614</a>
%H Stephan Mertens, <a href="https://arxiv.org/abs/2408.08053">Domination Polynomials of the Grid, the Cylinder, the Torus, and the King Graph</a>, arXiv:2408.08053 [math.CO], 2024. See p. 21.
%F a(n) = (A001333(n) + A001333(floor((n+2)/2))) / 2.
%t Table[((-I)^n ChebyshevT[n, I] + (-I)^# ChebyshevT[#, I])/2 &[Floor[(n + 2)/2]], {n, 0, 29}] (* _Michael De Vlieger_, Aug 22 2024 *)
%K nonn,easy
%O 0,3
%A _Christian G. Bower_