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 | 2 |
| 3 | 15 |
| 4 | 62 |
| 5 | 180 |
| 6 | 566 |
| 7 | 2419 |
| 8 | 9780 |
| 9 | 34958 |
| 10 | 125068 |
| 11 | 491958 |
| 12 | 1943862 |
| 13 | 7377378 |
| 14 | 27781250 |
| 15 | 107932937 |
| 16 | 422922350 |
| 17 | 1637252968 |
| 18 | 6306134498 |
| 19 | 24545899232 |
| 20 | 96073204466 |
| 21 | 374915623580 |
| 22 | 1459739914638 |
| 23 | 5704537068510 |
| 24 | 22360905044350 |