Centered heptagonal number

A centered heptagonal number is a centered figurate number that represents a heptagon with a dot in the center and all other dots surrounding the center dot in successive heptagonal layers.

The centered heptagonal number for n is given by the formula The first few centered heptagonal numbers are 1, 8, 22, 43, 71, 106, 148, 197, 253, 316, 386, 463, 547, 638, 736, 841, 953[1] A centered heptagonal prime is a centered heptagonal number that is prime.

The first few centered heptagonal primes are The centered heptagonal twin prime numbers are