Products k of 4 distinct primes (or tetraprimes) such that k has no squarefree neighbors.

Terms

a(0) =3774a(1) =5565a(2) =6726a(3) =8151a(4) =10659a(5) =10934a(6) =11726a(7) =11935a(8) =12426a(9) =13035a(10) =13195a(11) =13674a(12) =13755a(13) =14763a(14) =15042a(15) =15249a(16) =15351a(17) =15785a(18) =16215a(19) =16226a(20) =17630a(21) =17765a(22) =17974a(23) =17985a(24) =18249a(25) =18278a(26) =18915a(27) =18998a(28) =19565a(29) =20085