Numbers k such that k-4, k-2, k+2 and k+4 are prime.

Terms

a(0) =9a(1) =15a(2) =105a(3) =195a(4) =825a(5) =1485a(6) =1875a(7) =2085a(8) =3255a(9) =3465a(10) =5655a(11) =9435a(12) =13005a(13) =15645a(14) =15735a(15) =16065a(16) =18045a(17) =18915a(18) =19425a(19) =21015a(20) =22275a(21) =25305a(22) =31725a(23) =34845a(24) =43785a(25) =51345a(26) =55335a(27) =62985a(28) =67215a(29) =69495