A088558 Least odd leg of primitive Pythagorean triangles with even leg 4n.

3, 15, 5, 63, 21, 7, 45, 255, 77, 9, 117, 55, 165, 33, 11, 1023, 285, 65, 357, 39, 13, 105, 525, 247, 621, 153, 725, 15, 837, 119, 957, 4095, 85, 273, 51, 17, 1365, 345, 133, 231, 1677, 95, 1845, 57, 19, 513, 2205, 1015, 2397, 609, 253, 105, 2805, 713, 21, 207, 325