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powerful n.  and  practical n.

First numbers that belong to both sets:

1, 4, 8, 16, 32, 36, 64, 72, 100, 108, 128, 144, 196, 200, 216, 256, 288, 324, 392, 400, 432, 500, 512, 576, 648, 784, 800, 864, 900, 968, 972, 1000, 1024, 1152, 1296, 1352, 1372, 1568, 1600, 1728, 1764, 1800, 1936, 1944, 2000, 2048, 2304, 2500, 2592, 2700, 2704, 2744, 2916, 3136, 3200, 3456, 3528, 3600, 3872, 3888, 4000, 4096, 4356, 4500, 4608, 4624, 4900, 5000, 5184, 5292, 5400, 5408, 5488, 5776, 5832, 6084, 6272, 6400, 6912, 7056, 7200, 7744, 7776, 8000, 8100, 8192, 8464, 8712, 8748, 9000, 9216, 9248, 9604, 9800, 10000, 10368, 10404, 10584, 10648, 10800, 10816, 10976, 11552, 11664, 12100, 12168, 12348, 12500, 12544, 12800, 12996, 13068, 13456, 13500, 13824, 14112, 14400, 15376, 15488, 15552, 15876, 16000, 16200, 16384, 16900, 16928, 17424, 17496, 17576, 18000, 18252, 18432, 18496, 19044, 19208, 19600, 20000, 20736, 20808, 21168, 21296, 21600, 21632, 21952, 22500, 23104, 23328, 23716, 24200, 24300, 24336, 24500, 24696, 25000, 25088, 25600, 25992, 26136, 26244, 26912, 27000, 27648, 28224, 28800, 28900, 30276, 30752, 30976, 31104, 31212, 31752, 32000, 32400, 32768, 33124, 33800, 33856, 34300, 34596, 34848, 34992, 35152, 36000, 36100, 36504, 36864, 36992, 37044, 38088, 38416, 38988, 39200, 39204, 40000, 40500, 41472, 41616, 42336, 42592, 43200, 43264, 43808, 43904, 44100, 45000, 46208, 46656, 47432, 47628, 47916, 48400, 48600, 48672, 49000, 49284, 49392, 50000, 50176, 51200, 51984, 52272, 52488, 52900, 53792, 53824, 54000, 54756, 55296, 56448, 56644, 57132, 57600, 57800, 59168, 60500, 60516, 60552, 61504, 61952, 62208, 62424, 62500, 63504, 64000, 64800, 65536, 66248, 66564, 67228, 67500, 67600, 67712, 68600, 69192, 69696, 69984, 70304, 70688, 70756, 72000, 72200, 72900, 73008, 73728, 73984, 74088, 76176, 76832, 77976, 78400, 78408, 78608, 78732, 79092, 79524, 80000, 81000, 82944, 83232, 84100.

Some larger examples :