a(n) = a(n-1) + a(floor(n/2)) + a(ceiling(n/2)).

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =23a(5) =37a(6) =57a(7) =83a(8) =119a(9) =165a(10) =225a(11) =299a(12) =393a(13) =507a(14) =647a(15) =813a(16) =1015a(17) =1253a(18) =1537a(19) =1867a(20) =2257a(21) =2707a(22) =3231a(23) =3829a(24) =4521a(25) =5307a(26) =6207a(27) =7221a(28) =8375a(29) =9669