G.f.: Product_{m>0} (1 + x^m + 2*x^(2*m) + 3*x^(3*m)).

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =6a(5) =10a(6) =18a(7) =25a(8) =34a(9) =53a(10) =66a(11) =94a(12) =136a(13) =179a(14) =236a(15) =325a(16) =416a(17) =550a(18) =714a(19) =913a(20) =1181a(21) =1530a(22) =1917a(23) =2446a(24) =3091a(25) =3862a(26) =4828a(27) =6051a(28) =7457a(29) =9233