A015638 Number of ordered quadruples of integers from [ 2,n ] with no global factor.

0, 3, 9, 28, 50, 105, 169, 279, 406, 625, 839, 1202, 1570, 2086, 2646, 3461, 4219, 5358, 6452, 7899, 9381, 11404, 13240, 15805, 18272, 21383, 24461, 28520, 32107, 37066, 41706, 47395, 52968, 59990, 66312, 74747, 82553, 91969, 100989, 112468