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 | 1 |
| 2 | 10 |
| 3 | 55 |
| 4 | 265 |
| 5 | 1045 |
| 6 | 3817 |
| 7 | 12583 |
| 8 | 39148 |
| 9 | 114235 |
| 10 | 318857 |
| 11 | 850576 |
| 12 | 2190850 |
| 13 | 5451721 |
| 14 | 13184711 |
| 15 | 31023842 |
| 16 | 71286349 |
| 17 | 160139911 |
| 18 | 352574213 |
| 19 | 761567304 |
| 20 | 1616713932 |
| 21 | 3376143283 |
| 22 | 6944345483 |
| 23 | 14080091227 |
| 24 | 28169087367 |
| 25 | 55644767253 |
| 26 | 108617341172 |
| 27 | 209626751905 |