A031606 Numbers n such that continued fraction for sqrt(n) has odd period and central terms 18.

325, 2141, 4274, 6970, 7306, 10525, 10937, 14569, 15053, 18994, 20389, 24314, 25253, 25889, 30637, 31337, 36541, 43793, 47618, 51701, 52154, 52609, 53066, 54449, 55381, 62233, 70537, 71597, 72665, 80485, 81050, 82757, 83905, 85061, 85642, 86225, 86810