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) |
|---|---|
| 2 | 1 |
| 3 | 9 |
| 4 | 49 |
| 5 | 214 |
| 6 | 800 |
| 7 | 2685 |
| 8 | 8274 |
| 9 | 23829 |
| 10 | 64843 |
| 11 | 168223 |
| 12 | 418723 |
| 13 | 1005269 |
| 14 | 2337340 |
| 15 | 5281304 |
| 16 | 11629334 |
| 17 | 25015300 |
| 18 | 52670865 |
| 19 | 108745666 |
| 20 | 220489361 |
| 21 | 439619133 |
| 22 | 862952442 |
| 23 | 1669440245 |
| 24 | 3185892198 |
| 25 | 6002458625 |
| 26 | 11173532683 |
| 27 | 20564107275 |