%I #2 Mar 31 2012 13:21:56
%S 1,0,0,0,0,1,5,16,50,137,377,995,2617,6785,17630,45646,118595,308645,
%T 806617,2115455,5572438,14737430,39139779,104354064,279293860,
%U 750182992,2021884234,5466813137,14826008106,40322237818,109957234707
%N A000055(n+2)-A023359(n).
%Y Cf. A000055, A023359.
%K nonn
%O 0,7
%A _Jon Perry_, Jun 22 2003