Ulam numbers that are products of exactly four distinct primes (or tetraprimes).

Terms

a(0) =390a(1) =546a(2) =690a(3) =798a(4) =1155a(5) =1230a(6) =1770a(7) =2010a(8) =2090a(9) =2418a(10) =2618a(11) =2814a(12) =3090a(13) =3290a(14) =3390a(15) =3930a(16) =4326a(17) =4370a(18) =4470a(19) =4578a(20) =4602a(21) =4641a(22) =6110a(23) =6870a(24) =7170a(25) =7490a(26) =7735a(27) =7930a(28) =8294a(29) =9834