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alternating n.  and  semiprime

First numbers that belong to both sets:

4, 6, 9, 10, 14, 21, 25, 34, 38, 49, 58, 65, 69, 74, 85, 87, 94, 121, 123, 129, 141, 143, 145, 161, 169, 183, 185, 187, 214, 218, 254, 274, 278, 298, 301, 303, 305, 309, 321, 323, 327, 329, 341, 361, 365, 381, 454, 458, 478, 501, 505, 527, 529, 543, 545, 565, 581, 583, 589, 614, 634, 674, 694, 698, 703, 707, 721, 723, 745, 749, 763, 767, 781, 785, 789, 818, 838, 878, 898, 901, 905, 921, 923, 943, 949, 961, 965, 985, 989, 1018, 1094, 1214, 1234, 1238, 1294, 1418, 1438, 1454, 1478, 1618, 1654, 1658, 1678, 1814, 1838, 1858, 1874, 1894, 2101, 2103, 2105, 2123, 2127, 2147, 2149, 2165, 2167, 2181, 2183, 2189, 2305, 2307, 2321, 2323, 2327, 2329, 2361, 2363, 2369, 2501, 2507, 2509, 2545, 2561, 2563, 2567, 2569, 2581, 2587, 2589, 2701, 2705, 2721, 2723, 2743, 2747, 2761, 2785, 2787, 2901, 2921, 2923, 2929, 2941, 2947, 2949, 2965, 2981, 2983, 2987, 3098, 3214, 3218, 3238, 3254, 3274, 3418, 3494, 3694, 3814, 3898, 4101, 4103, 4105, 4109, 4121, 4141, 4143, 4145, 4163, 4169, 4181, 4183, 4187, 4189, 4303, 4307, 4309, 4321, 4341, 4343, 4367, 4369, 4381, 4385, 4387, 4501, 4529, 4541, 4569, 4589, 4701, 4705, 4709, 4727, 4741, 4747, 4749, 4763, 4765, 4769, 4781, 4907, 4927, 4963, 4981, 4985, 4989, 5078, 5098, 5218, 5234, 5294, 5414, 5438, 5458, 5498, 5638, 5674, 5818, 5834, 5854, 5878, 6103, 6107, 6109, 6127, 6145, 6161, 6167, 6169, 6181, 6185, 6187, 6189, 6341, 6347, 6349, 6383, 6385, 6387, 6503, 6505, 6509, 6523, 6527, 6541, 6583, 6587, 6589, 6707, 6729, 6743, 6749, 6767, 6769, 6787, 6901, 6905, 6927, 6941, 6943, 6989, 7034, 7054, 7058, 7078, 7094, 7214, 7234.

Some larger examples :