a(0)=0; a(1)=1; a(n) = Sum_{k=1..[sqrt(n)]} a(n-k) for n>=2.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =5a(7) =8a(8) =13a(9) =26a(10) =47a(11) =86a(12) =159a(13) =292a(14) =537a(15) =988a(16) =1976a(17) =3793a(18) =7294a(19) =14051a(20) =27114a(21) =52252a(22) =100711a(23) =194128a(24) =374205a(25) =748410a(26) =1469706a(27) =2887160a(28) =5673609a(29) =11153090