a(n) = Sum_{k|n} a(k) a(n-k) for n >= 2, a(0)=0, a(1)=1.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =5a(7) =5a(8) =14a(9) =19a(10) =37a(11) =37a(12) =146a(13) =146a(14) =317a(15) =537a(16) =1342a(17) =1342a(18) =4312a(19) =4312a(20) =13751a(21) =19648a(22) =34768a(23) =34768a(24) =178350a(25) =205852a(26) =405518a(27) =665796a(28) =1626743a(29) =1626743