A091012 Numbers having exactly one divisor d such that for some x also d-x and d+x are divisors.

6, 15, 28, 40, 91, 153, 190, 220, 325, 496, 544, 561, 572, 627, 703, 861, 897, 935, 946, 1012, 1225, 1287, 1292, 1431, 1581, 1610, 1653, 1768, 1891, 2278, 2300, 2465, 2618, 2701, 2967, 3321, 3344, 3496, 3596, 3655, 3952, 4123, 4301, 4324, 4371