Numbers on the square spiral board that are enclosed by four primes.

Terms

a(0) =12a(1) =72a(2) =1152a(3) =1452a(4) =1950a(5) =3672a(6) =5520a(7) =6660a(8) =8232a(9) =10302a(10) =10890a(11) =13218a(12) =15288a(13) =15360a(14) =16062a(15) =18042a(16) =20898a(17) =21018a(18) =23628a(19) =25998a(20) =27918a(21) =32190a(22) =37812a(23) =42018a(24) =42462a(25) =48858a(26) =55818a(27) =57192a(28) =80832a(29) =80910