%I #9 Oct 23 2022 23:32:16
%S 1,1,1,2,4,6,14,28,68,156,399,1012,2732,7385,20665,58377,168119,488771
%N Number of connected graphs with n edges embeddable into square lattice.
%C a(n) <= number of connected planar graphs with n edges A046091.
%H Andreas R. Hehn, <a href="https://doi.org/10.3929/ethz-a-010742232">Series Expansion Methods for Quantum Lattice Models</a>, Doctoral Thesis, ETH Zürich, 2016.
%e For n = 3 there are a(3) = 2 graphs: the claw graph, corresponding to a single free polystick, and the 3-path, corresponding to 4 different free polysticks.
%Y Cf. A046091, A019988 (embeddings, or free polysticks), A255539 (with n nodes, neighbors connected).
%K nonn,more
%O 0,4
%A I. E. Kashuba (kashuba(AT)bitp.kiev.ua), Oct 27 2010
%E Terms a(16)-a(17) from Hehn Table 3.1 and a(0) = 1 added by _Andrey Zabolotskiy_, Oct 22 2022
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