Cuban primes 2: Primes of the form 3y^2+6y+4.
There is 18 Cuban primes 2 smaller than 28220.
Checkout Cuban primes 2 up to: 100, 500, 1000, 10000.
13, 109, 193, 433, 769, 1201, 1453, 2029, 3469, 3889, 4801, 10093, 12289, 13873, 18253, 20173, 21169, 22189