G.f.: (1+x^6)/((1-x)*(1-x^3)*(1-x^4)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =3a(6) =5a(7) =6a(8) =7a(9) =9a(10) =11a(11) =12a(12) =15a(13) =17a(14) =19a(15) =22a(16) =25a(17) =27a(18) =31a(19) =34a(20) =37a(21) =41a(22) =45a(23) =48a(24) =53a(25) =57a(26) =61a(27) =66a(28) =71a(29) =75