%I M1057 #25 Jun 26 2017 23:00:56
%S 0,1,1,2,4,7,12,20,33,54,90,148,244,403,665,1096,1808,2980,4914,8103,
%T 13359,22026,36315,59874,98715,162754,268337,442413,729416,1202604,
%U 1982759,3269017,5389698,8886110,14650719,24154952,39824784
%N a(n) = floor(e^((n-1)/2)).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H R. K. Guy and N. J. A. Sloane, <a href="/A005180/a005180.pdf">Correspondence</a>, 1988.
%t Floor[E^((Range[0,40]-1)/2)] (* _Harvey P. Dale_, Mar 20 2016 *)
%K nonn
%O 0,4
%A _N. J. A. Sloane_, _R. K. Guy_