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 | 3 |
| 3 | 23 |
| 4 | 132 |
| 5 | 729 |
| 6 | 3987 |
| 7 | 18687 |
| 8 | 82350 |
| 9 | 342383 |
| 10 | 1295579 |
| 11 | 4634280 |
| 12 | 15873501 |
| 13 | 51143461 |
| 14 | 156932559 |
| 15 | 463212189 |
| 16 | 1309275981 |
| 17 | 3576241449 |
| 18 | 9484669665 |
| 19 | 24306269493 |
| 20 | 60475548510 |
| 21 | 146630200929 |
| 22 | 345755185335 |
| 23 | 796397380425 |
| 24 | 1797676089003 |
| 25 | 3970398558042 |
| 26 | 8602390112508 |