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deficient n.  and  octagonal n.

First numbers that belong to both sets:

1, 8, 21, 65, 133, 225, 341, 481, 645, 833, 1045, 1281, 1541, 1825, 2133, 2465, 2821, 3201, 3605, 4033, 4485, 4961, 5461, 6533, 7105, 7701, 8321, 8965, 9633, 9976, 10325, 11041, 11781, 12545, 13333, 14145, 14981, 15841, 16725, 17176, 17633, 18565, 19521, 20008, 20501, 21505, 22533, 23585, 24661, 25208, 25761, 26885, 28033, 29205, 30401, 31621, 32865, 33496, 34133, 35425, 36741, 38081, 39445, 40136, 40833, 42245, 43681, 45141, 46625, 48133, 51221, 52801, 54405, 56033, 57685, 59361, 61061, 62785, 63656, 64533, 66305, 68101, 69921, 71765, 73633, 74576, 75525, 77441, 79381, 81345, 83333, 85345, 87381, 88408, 89441, 91525, 93633, 95765, 97921, 100101, 102305, 104533, 105656, 109061, 111361, 113685, 116033, 118405, 120801, 122008, 123221, 125665, 128133, 130625, 133141, 134408, 135681, 138245, 140833, 142136, 143445, 146081, 148741, 151425, 154133, 156865, 159621, 162401, 165205, 166616, 168033, 170885, 173761, 176661, 179585, 182533, 185505, 188501, 191521, 194565, 197633, 200725, 203841, 206981, 210145, 213333, 214936, 216545, 219781, 223041, 226325, 229633, 232965, 236321, 239701, 243105, 246533, 249985, 253461, 256961, 260485, 262256, 264033, 265816, 267605, 271201, 273008, 274821, 278465, 282133, 285825, 289541, 293281, 300833, 304645, 308481, 312341, 316225, 320133, 322096, 324065, 328021, 332001, 336005, 340033, 344085, 348161, 352261, 356385, 360533, 364705, 368901, 373121, 377365, 381633, 385925, 390241, 392408, 394581, 398945, 403333, 412181, 416641, 421125, 423376, 425633, 430165, 434721, 439301, 443905, 448533, 453185, 457861, 462561, 467285, 472033, 474416, 476805, 481601, 486421, 491265, 496133, 501025, 505941, 508408, 510881, 515845, 520833, 525845, 530881, 535941, 541025, 546133, 548696, 551265, 556421, 561601, 566805, 569416, 572033, 577285, 582561, 587861, 593185, 595856, 598533, 603905, 609301, 612008, 614721, 620165, 625633, 636641, 642181, 647745, 650536, 653333, 658945, 664581, 670241, 675925, 681633, 684496, 687365, 693121, 696008, 698901, 704705, 710533, 716385, 722261, 728161, 734085, 740033, 746005, 752001, 758021, 764065, 770133, 773176.

Some larger examples :