a(0)=1; thereafter a(n) = Sum_{k=2..n+1} A006206(k).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =7a(6) =11a(7) =16a(8) =24a(9) =35a(10) =53a(11) =78a(12) =118a(13) =176a(14) =266a(15) =401a(16) =611a(17) =927a(18) =1419a(19) =2169a(20) =3333a(21) =5124a(22) =7910a(23) =12215a(24) =18925a(25) =29345a(26) =45609a(27) =70959a(28) =110609a(29) =172576