From a partition of the integers.

Terms

a(0) =1a(1) =3a(2) =7a(3) =17a(4) =31a(5) =42a(6) =54a(7) =122a(8) =143a(9) =167a(10) =211a(11) =258a(12) =414a(13) =469a(14) =525a(15) =582a(16) =640a(17) =699a(18) =759a(19) =820a(20) =882a(21) =945a(22) =1009a(23) =1075a(24) =1458a(25) =1539a(26) =1621