a(n) is the number of partitions of n into parts not greater than A020639(n).

Terms

a(0) =1a(1) =2a(2) =3a(3) =3a(4) =7a(5) =4a(6) =15a(7) =5a(8) =12a(9) =6a(10) =56a(11) =7a(12) =101a(13) =8a(14) =27a(15) =9a(16) =297a(17) =10a(18) =490a(19) =11a(20) =48a(21) =12a(22) =1255a(23) =13a(24) =377a(25) =14a(26) =75a(27) =15a(28) =4565a(29) =16