Search a number
heptagonal n.  and  tau n.

First numbers that belong to both sets:

1, 18, 3744, 5688, 30636, 35820, 63760, 91872, 133056, 163456, 173844, 321664, 446688, 516880, 553896, 575280, 736308, 760932, 828576, 899100, 944640, 1349460, 1473408, 1626912, 1725156, 1895296, 3128724, 3134320, 3179268, 3544416, 3598200, 3986028, 4094080, 4513824, 5003440, 5181840, 5895936, 6199200, 6582888, 7522960, 7741360, 8452044, 8974720, 9213120, 9591264, 9917172, 10554480, 10812880, 11307132, 11403036, 11563776, 13267584, 13720608, 13826232, 14396400, 14480512, 15571296, 18059328, 18383292, 18491920, 19820416, 20731680, 21297024, 23205952, 26629344, 26874684, 27022428, 27683968, 27800560, 28218960, 29424256, 30532320, 33264288, 33392080, 33850480, 34423236, 34441792, 36379840, 37610784, 38862208, 39495600, 39994000, 40154148, 40636512, 42904908, 45426528, 46111120, 46132596, 47343232, 49610880, 50169280, 52525764, 53077248, 53817040, 55877868, 59114628, 59138944, 60878160, 61496560, 61670272, 64482984, 65528320, 67176864, 69029680, 72245376, 72891900, 73297440, 75040384, 75726784, 77916348, 78167772, 78587712, 84062304, 84323448, 86662528, 87607120, 88556832, 89721216, 90712404, 94823964, 96556240, 97334640, 100352736, 105712768, 106755760, 107574160, 109915456, 113693724, 118291284, 120780576, 122454504, 123015040, 123612012, 126156384, 128403972, 129589200, 133615836, 137778304, 140164128, 140426320, 141628032, 152673840, 154909152, 157438336, 161551744, 162558144, 164134368, 165433360, 170391456, 172005120, 173376468, 177354688, 178409088, 178704880, 179763280, 182786176, 186611040, 191436876, 192488400, 200690560, 203567904, 206465728, 207922320, 210804948, 211172416, 211218372, 214123680, 217888236, 221591440, 222769840, 224282752, 232261344, 238129360, 239693472, 242837056, 245158668, 249185664, 252742480, 252792756, 254353792, 258862176, 260850240, 267480324, 269086000, 270748512, 275399296, 278768160, 280831104, 282104388, 285941520, 287279920, 290289276, 294561280, 295919680, 297608436, 301549248, 302923648, 303309040, 306013644, 308619136, 312184800, 313527204, 314031348, 324882900, 334008864, 337717888, 338182956, 339172288, 341038480, 342909792, 356570208, 359982000, 360402112, 361904512, 368127360, 373058316, 377468928, 377899120, 389357280, 399405040, 399847552, 401429952, 403904736, 408493548, 413686944, 419884560, 426128256, 428677920, 432878464, 438753888, 440876080, 446738508, 451563840, 454188384, 460206208, 460681200, 462923748, 464558112, 465581052, 467220096, 491099616, 502872448, 505144240, 506353212, 518378400, 522996544, 529962160, 530471872, 532294272, 535143456, 539835520, 547503804, 551655280, 553513680, 570304384, 575147808, 580011712, 589800960, 591645564, 607674816, 609625216, 614005452, 617693824, 622734048, 625261840, 650256768, 650821360, 652839760, 653405472, 658589056, 660619456, 665831520, 669017664, 676892880, 692199040, 700795008, 705574800, 716960160, 718993764, 724515904.

Some larger examples :