G.f.: Sum_{n>0} x^n/(1-x^(3n)) = Sum_{n>=0} x^(3n+1)/(1-x^(3n+1)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =1a(5) =1a(6) =2a(7) =2a(8) =1a(9) =2a(10) =1a(11) =2a(12) =2a(13) =2a(14) =1a(15) =3a(16) =1a(17) =1a(18) =2a(19) =3a(20) =2a(21) =2a(22) =1a(23) =2a(24) =2a(25) =2a(26) =1a(27) =4a(28) =1a(29) =2