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Harshad n.  and  octagonal n.

First numbers that belong to both sets:

1, 8, 21, 40, 133, 225, 280, 408, 481, 645, 736, 936, 1160, 1680, 2133, 2465, 2640, 2821, 3816, 8640, 10680, 12160, 12936, 14145, 14560, 15408, 18096, 19040, 21000, 23056, 24120, 27456, 31008, 34776, 38760, 42245, 50440, 58520, 60208, 61920, 64533, 67200, 77441, 78408, 84336, 99008, 100101, 101200, 106785, 107920, 110208, 117216, 124440, 131880, 139536, 144760, 147408, 150080, 158240, 161008, 163800, 165205, 172320, 176661, 179585, 190008, 210145, 216545, 218160, 221408, 243105, 258720, 287680, 291408, 302736, 306560, 314280, 326040, 330008, 332001, 334000, 336005, 338016, 350208, 362616, 368901, 390241, 405536, 421125, 427896, 434721, 437008, 441600, 450856, 469656, 484008, 491265, 498576, 503480, 513360, 518336, 523336, 528360, 541025, 559008, 590520, 593185, 601216, 606600, 644960, 673080, 687365, 707616, 725208, 749000, 761040, 770133, 785408, 791560, 810160, 835296, 848008, 873720, 926296, 932976, 939680, 953160, 963333, 966736, 973560, 994176, 1001096, 1022000, 1036056, 1039585, 1050208, 1057320, 1078800, 1096865, 1111425, 1122408, 1137136, 1144536, 1155681, 1166880, 1231361, 1242920, 1258416, 1281840, 1289696, 1321360, 1337336, 1353408, 1365525, 1398101, 1402200, 1426920, 1468600, 1477008, 1481221, 1502376, 1506625, 1527960, 1536536, 1575425, 1601621, 1610401, 1614800, 1659120, 1713096, 1740408, 1795680, 1823640, 1833008, 1837701, 1889720, 1937640, 1966680, 2025408, 2035280, 2040225, 2080001, 2085000, 2100033, 2115120, 2176008, 2217080, 2237760, 2258536, 2321440, 2332008, 2342600, 2363856, 2374520, 2385208, 2395920, 2428200, 2439008, 2444421, 2482480, 2504360, 2526336, 2559480, 2565025, 2592840, 2615200, 2660208, 2705600, 2832408, 2849925, 2861633, 2914616, 2986016, 2992005, 3010008, 3064341, 3070408, 3082560, 3106936, 3155976, 3193008, 3217816, 3224033, 3242720, 3305400, 3458280, 3497040, 3523000, 3536016, 3549056, 3562120, 3608033, 3654240, 3674133, 3687425, 3694080, 3774408, 3855600, 3923920, 3944533, 3965200, 3979008, 4020576, 4027525, 4048408, 4104360, 4132480, 4210305, 4231656, 4274520, 4317600, 4360896, 4389880, 4404408, 4426245, 4536240, 4610320, 4625208, 4662533, 4670016, 4745176, 4836160, 4920321, 4928008, 4943400, 5020720, 5036256, 5083008, 5224560, 5248341, 5320008, 5416320, 5464800, 5481008, 5619745, 5743600, 5810208, 5902421, 5910840, 6037845.

Some larger examples :