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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 15 |
| 4 | 207 |
| 5 | 1347 |
| 6 | 5922 |
| 7 | 20307 |
| 8 | 58527 |
| 9 | 148239 |
| 10 | 339669 |
| 11 | 718344 |
| 12 | 1422564 |
| 13 | 2666664 |
| 14 | 4771221 |
| 15 | 8201466 |
| 16 | 13615266 |
| 17 | 21922146 |
| 18 | 34354926 |
| 19 | 52555653 |
| 20 | 78677613 |
| 21 | 115505313 |
| 22 | 166594428 |
| 23 | 236433813 |
| 24 | 330631785 |
| 25 | 456128985 |
| 26 | 621440235 |
| 27 | 836927910 |
| 28 | 1115109450 |