Numbers k that divide s(k), where s(1)=1, s(j)=15*s(j-1)+j.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =15a(5) =21a(6) =35a(7) =49a(8) =55a(9) =105a(10) =147a(11) =165a(12) =245a(13) =343a(14) =385a(15) =605a(16) =723a(17) =735a(18) =903a(19) =915a(20) =1029a(21) =1155a(22) =1715a(23) =1815a(24) =2401a(25) =2485a(26) =2695a(27) =3615a(28) =3685a(29) =4235