Search a number
heptagonal n.  and  practical n.

First numbers that belong to both sets:

1, 18, 112, 342, 540, 616, 1288, 1404, 1782, 3186, 3744, 5688, 6426, 7480, 8910, 9828, 12496, 12852, 13950, 15484, 17514, 18792, 22420, 22896, 24354, 26368, 28998, 30636, 35224, 35820, 37638, 40768, 43362, 45360, 51624, 53802, 60606, 62964, 69472, 70308, 72846, 76300, 80730, 83448, 84364, 90916, 91872, 94770, 98704, 103734, 106812, 107848, 115240, 116316, 119574, 129618, 133056, 143640, 147258, 152152, 158382, 162180, 173844, 177822, 190026, 194184, 195580, 205492, 206928, 211266, 217120, 218596, 224550, 229068, 242892, 247590, 261954, 266832, 280060, 281736, 286794, 293608, 302238, 307476, 309232, 321664, 323460, 328878, 338008, 345402, 351000, 368064, 373842, 381616, 383572, 391446, 397404, 413512, 415548, 421686, 429940, 432016, 440370, 446688, 465912, 472410, 483340, 492174, 498852, 516880, 519156, 526014, 537544, 546858, 553896, 575280, 582498, 592192, 604422, 611820, 634284, 641862, 652036, 672624, 675220, 693532, 696168, 704106, 728190, 739024, 758176, 760932, 769230, 794394, 802872, 825700, 828576, 848848, 863478, 872316, 896104, 899100, 908118, 935442, 944640, 947716, 972504, 981882, 997612, 1010286, 1019844, 1023040, 1048788, 1058526, 1088010, 1097928, 1127952, 1138050, 1151584, 1154980, 1168614, 1178892, 1182328, 1206520, 1209996, 1220454, 1252098, 1262736, 1294920, 1305738, 1338462, 1349460, 1379008, 1382724, 1393902, 1412632, 1427706, 1439064, 1473408, 1484946, 1500400, 1519830, 1531548, 1563016, 1566972, 1578870, 1598800, 1614834, 1626912, 1663416, 1675674, 1712718, 1762740, 1775358, 1792252, 1813482, 1826280, 1830556, 1860628, 1864944, 1877922, 1895296, 1930284, 1970028, 1983366, 2001220, 2005696, 2023650, 2037168, 2077992, 2091690, 2110024, 2133054, 2146932, 2184160, 2188836, 2202894, 2259576, 2264332, 2302560, 2316978, 2341108, 2360502, 2375100, 2419164, 2433942, 2478546, 2493504, 2498500, 2538648, 2574040, 2599470, 2614788, 2619904, 2655856, 2661012, 2676510, 2723274, 2738952, 2786256, 2802114, 2828644, 2849958, 2865996, 2871352, 2908984, 2914380, 2930598, 2979522, 2995920, 3045384, 3061962, 3084136, 3111966, 3134320, 3173632, 3179268, 3196206, 3224536, 3247290, 3264408, 3316032, 3333330, 3356464, 3362260, 3385494, 3402972, 3408808, 3449800, 3455676, 3496948, 3526578, 3544416, 3550372, 3592204, 3598200, 3640312, 3670542, 3688740, 3694816.

Some larger examples :