Related to a highly composite sequence (A002497).

Terms

a(0) =3a(1) =7a(2) =12a(3) =19a(4) =30a(5) =43a(6) =49a(7) =53a(8) =70a(9) =89a(10) =112a(11) =141a(12) =172a(13) =209a(14) =250a(15) =293a(16) =301a(17) =348a(18) =368a(19) =421a(20) =480