a(1) = a(2) = 1; a(n+2) = 1 + Sum_{d|n} a(n/d) * a(d).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =8a(6) =11a(7) =21a(8) =23a(9) =49a(10) =51a(11) =109a(12) =103a(13) =247a(14) =207a(15) =517a(16) =435a(17) =1086a(18) =871a(19) =2251a(20) =1743a(21) =4631a(22) =3531a(23) =9365a(24) =7063a(25) =19081a(26) =14152a(27) =38369a(28) =28397a(29) =77299