a(n) = m is the least m = b*c > a(n-1) such that (b+c)*n = m-1 where 1 < b <= c < m.

Terms

a(0) =6a(1) =21a(2) =40a(3) =105a(4) =126a(5) =301a(6) =456a(7) =657a(8) =910a(9) =1221a(10) =1596a(11) =2041a(12) =2562a(13) =3165a(14) =3856a(15) =4641a(16) =5526a(17) =6517a(18) =7620a(19) =8841a(20) =10186a(21) =11661a(22) =13272a(23) =15025a(24) =16926a(25) =18981a(26) =21196a(27) =23577a(28) =26130a(29) =28861