|
|
When d=6, the coprimes are 1 and 5, so the center is not very dense. When d=30, the coprimes are 1, 7, 11, 13, 17, 19, 23, 29, so the center is dense. When d=210, the coprimes are 1, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 143, 149, 151, 157, 163, 167, 169, 173, 179, 181, 187, 191, 193, 197, 199, 209, so the center is very dense.
|