a(n) = 1 if a(n-1) is prime, else a(n) = a(n-2)+a(n-3); starting with a(0) = 0, a(1) = a(2) = 1.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =3a(7) =1a(8) =4a(9) =4a(10) =5a(11) =1a(12) =9a(13) =6a(14) =10a(15) =15a(16) =16a(17) =25a(18) =31a(19) =1a(20) =56a(21) =32a(22) =57a(23) =88a(24) =89a(25) =1a(26) =177a(27) =90a(28) =178a(29) =267