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%I M3178 #15 Jan 04 2021 14:09:04
%S 1,3,355,297619,1120452771,15350524923547,738416821509929731,
%T 126430202628042630866787,78847417416749666369637926851,
%U 183373380693566591129149674727445419,1623847327688450079238401833083018045926051,55669578575421273854874611540671620662810228887603
%N Number of labeled nonseparable (or 2-connected) bipartite graphs with 2n nodes.
%C Nonseparable graphs are also called blocks.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H Andrew Howroyd, <a href="/A005336/b005336.txt">Table of n, a(n) for n = 1..50</a>
%H F. Harary and R. W. Robinson, <a href="http://dx.doi.org/10.4153/CJM-1979-007-3">Labeled bipartite blocks</a>, Canad. J. Math., 31 (1979), 60-68.
%Y Bisection of A004100.
%Y Cf. A005334, A005335 (each part with n nodes).
%K nonn
%O 1,2
%A _N. J. A. Sloane_
%E Name clarified and more terms added by _Andrew Howroyd_, Jan 03 2021