A113844 - OEIS

A113844

a(1) =a(2) =1. a(n+1) = (sum{1<=k<=n/2} a(k)) * (sum{n/2<j<=n} a(j)).

%I #5 Apr 09 2014 10:12:21

%S 1,1,1,2,6,18,78,312,2070,12420,163878,1966536,62213526,1866405780,

%T 206591803854,22311914816232,9436063264020024,3963146570888410080,

%U 9887814229774042889370,24620657432137366794531300

%N a(1) =a(2) =1. a(n+1) = (sum{1<=k<=n/2} a(k)) * (sum{n/2<j<=n} a(j)).

%e a(8) = (a(1)+a(2)+a(3)) * (a(4)+a(5)+a(6)+a(7)) =

%e (1+1+1) * (2+6+18+78) = 312.

%K easy,nonn

%O 1,4

%A _Leroy Quet_, Jan 24 2006

%E More terms from Evonne Haines (avissean(AT)adelphia.net), Jan 28 2006