Number of partitions of n if there are two kinds of 1's and two kinds of 2's.

Terms

a(0) =1a(1) =2a(2) =5a(3) =9a(4) =17a(5) =28a(6) =47a(7) =73a(8) =114a(9) =170a(10) =253a(11) =365a(12) =525a(13) =738a(14) =1033a(15) =1422a(16) =1948a(17) =2634a(18) =3545a(19) =4721a(20) =6259a(21) =8227a(22) =10767a(23) =13990a(24) =18105a(25) =23286a(26) =29837a(27) =38028a(28) =48297a(29) =61053