Sequence of the "Natural Jewels": a natural jewel is a number that is totally enclosed by prime numbers in a version of Ulam Spiral.

A172294

Sequence of the "Natural Jewels": a natural jewel is a number that is totally enclosed by prime numbers in a version of Ulam Spiral.

Terms

    a(0) =12a(1) =42a(2) =1152a(3) =1452a(4) =1950a(5) =3672a(6) =5520a(7) =6660a(8) =8232a(9) =10890a(10) =13218a(11) =15288a(12) =15360a(13) =16062a(14) =18042a(15) =20898a(16) =21018a(17) =23562a(18) =23628a(19) =25998a(20) =27918a(21) =32190a(22) =37812a(23) =42018a(24) =42462a(25) =48858a(26) =55818a(27) =57192a(28) =80832a(29) =80910

External references