%I #19 Aug 27 2016 10:33:24
%S 1,1,1,1,1,4,10,55,649,38881,6414706,24978826228,2913605221297249,
%T 112139525368095766797655,8403341152380185679389503620974065,
%U 146904111947501701959735285821948223340424963459227
%N a(0) = a(1) = a(2) = a(3) = a(4) = 1; for n>4, a(n) = ( a(n-1) +a(n-3) )*( a(n-2)+a(n-4) ) / a(n-5).
%H Seiichi Manyama, <a href="/A276130/b276130.txt">Table of n, a(n) for n = 0..22</a>
%F a(n) = (9-3*(-1)^n)/2*a(n-1)*a(n-3)-a(n-2)-a(n-4).
%o (PARI) a(n) = if (n<=4, 1, (9-3*(-1)^n)/2*a(n-1)*a(n-3)-a(n-2)-a(n-4)); \\ _Michel Marcus_, Aug 27 2016
%Y Cf. A006721.
%K nonn
%O 0,6
%A _Bruno Langlois_, Aug 21 2016