a(n+1) = Sum_{k=0..floor(2*n/5)} a(k) * a(n-k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =6a(7) =11a(8) =20a(9) =40a(10) =77a(11) =160a(12) =319a(13) =636a(14) =1332a(15) =2721a(16) =5799a(17) =12068a(18) =25109a(19) =53943a(20) =113682a(21) =245931a(22) =523896a(23) =1115239a(24) =2425858a(25) =5208339a(26) =11388934a(27) =24630843a(28) =53194684a(29) =116764483