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 | 10 |
| 4 | 50 |
| 5 | 214 |
| 6 | 802 |
| 7 | 2802 |
| 8 | 9275 |
| 9 | 29580 |
| 10 | 91668 |
| 11 | 277924 |
| 12 | 828092 |
| 13 | 2433140 |
| 14 | 7067885 |
| 15 | 20337318 |
| 16 | 58054534 |
| 17 | 164602410 |
| 18 | 463990190 |
| 19 | 1301338150 |
| 20 | 3633753815 |
| 21 | 10107239160 |
| 22 | 28016346216 |
| 23 | 77419909800 |
| 24 | 213349801560 |
| 25 | 586471432104 |
| 26 | 1608485221177 |
| 27 | 4402406713762 |