%I #2 Apr 30 2014 01:26:49

%S 1,2,0,8,80,1152,21056,467840,12248064,369313280,12605643776,

%T 480491716608,20231074672640,932551401807872,46708494389084160,

%U 2525988902617776128,146694190329387352064,9105143756032486932480

%N Expansion of 2 - exp(-1 + sqrt(1-4x)).

%Y Cf. A000806.

%K nonn

%O 0,2

%A _Ralf Stephan_, Dec 13 2004