a(n) = Sum_{k=0..(n-2)/2} a(k)a*(n-1-k), with a(0) = a(1) = 1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =6a(7) =11a(8) =22a(9) =42a(10) =87a(11) =174a(12) =365a(13) =745a(14) =1587a(15) =3303a(16) =7103a(17) =14974a(18) =32477a(19) =69284a(20) =151172a(21) =325077a(22) =713400a(23) =1545719a(24) =3406989a(25) =7423648a(26) =16429555a(27) =35992438a(28) =79912474a(29) =175785514