%I M2672 #11 Feb 16 2022 10:26:34
%S 1,3,7,19,49,127,321,813,2041,5117,12763,31791,78917,195677,483997,
%T 1196081,2950439,7271905
%N Expansion of layer susceptibility series for square lattice.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H I. G. Enting and A. J. Guttmann, <a href="https://doi.org/10.1088/0305-4470/13/3/037">The square lattice Ising model with a free surface</a>, J. Phys. A: Math. Gen. 13 (1980), 1043-1050.
%H S. G. Whittington, G. M. Torrie and A. J. Guttmann, <a href="https://doi.org/10.1088/0305-4470/12/12/023">The Ising model with a free surface: a series analysis study</a>, J. Phys. A 12 (1979), 2449-2455.
%Y Cf. A007287 (cubic).
%K nonn,more
%O 0,2
%A _Simon Plouffe_
%E a(14) corrected, a(15)-a(17) from Enting & Guttmann added by _Andrey Zabolotskiy_, Feb 16 2022