%I M1710 #20 Jun 17 2022 16:19:31
%S 2,6,38,684,50224,13946352,14061131152,50947324188128,
%T 666754350781269760,31763991166456912086656,
%U 5550343429517595744902558208,3581353054755185129132443153728000
%N Switching classes of digraphs.
%D R. C. Read, personal communication.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H R. C. Read, <a href="/A000684/a000684_1.pdf">Letter to N. J. A. Sloane, Oct. 29, 1976</a>
%Y Cf. A002854, A049313.
%K nonn,nice
%O 1,1
%A _N. J. A. Sloane_
%E More terms from _Vladeta Jovovic_, Jul 22 2000