Number of partitions into one kind of 1's, two kinds of 2's, and three kinds of 3's.

Terms

a(0) =1a(1) =1a(2) =3a(3) =6a(4) =9a(5) =15a(6) =25a(7) =34a(8) =51a(9) =73a(10) =97a(11) =132a(12) =178a(13) =226a(14) =294a(15) =376a(16) =466a(17) =582a(18) =722a(19) =872a(20) =1062a(21) =1282a(22) =1522a(23) =1812a(24) =2147a(25) =2507a(26) =2937a(27) =3422a(28) =3947a(29) =4557