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) |
|---|---|
| 9 | 1 |
| 10 | 9 |
| 11 | 89 |
| 12 | 639 |
| 13 | 4082 |
| 14 | 23191 |
| 15 | 122381 |
| 16 | 607944 |
| 17 | 2887756 |
| 18 | 13229876 |
| 19 | 58898404 |
| 20 | 256121253 |
| 21 | 1092452270 |
| 22 | 4585149401 |
| 23 | 18985099139 |
| 24 | 77707979700 |
| 25 | 314944855135 |
| 26 | 1265638606115 |
| 27 | 5048705160315 |
| 28 | 20010229736469 |
| 29 | 78861912700117 |
| 30 | 309252947330313 |
| 31 | 1207359268831473 |