This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 21 |
| 2 | 168 |
| 3 | 840 |
| 4 | 3150 |
| 5 | 9702 |
| 6 | 25872 |
| 7 | 61776 |
| 8 | 135135 |
| 9 | 275275 |
| 10 | 528528 |
| 11 | 965328 |
| 12 | 1689324 |
| 13 | 2848860 |
| 14 | 4651200 |
| 15 | 7379904 |
| 16 | 11415789 |
| 17 | 17261937 |
| 18 | 25573240 |
| 19 | 37191000 |
| 20 | 53183130 |
| 21 | 74890530 |
| 22 | 103980240 |
| 23 | 142506000 |
| 24 | 192976875 |
| 25 | 258434631 |
| 26 | 342540576 |
| 27 | 449672608 |
| 28 | 585033240 |
| 29 | 754769400 |