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 | 18 |
| 2 | 84 |
| 3 | 312 |
| 4 | 1352 |
| 5 | 5908 |
| 6 | 26490 |
| 7 | 120278 |
| 8 | 552032 |
| 9 | 2553972 |
| 10 | 11892734 |
| 11 | 55672118 |
| 12 | 261759734 |
| 13 | 1235323302 |
| 14 | 5848421012 |
| 15 | 27764530552 |
| 16 | 132124679472 |
| 17 | 630077734772 |
| 18 | 3010344270942 |
| 19 | 14406602755262 |
| 20 | 69048608938842 |
| 21 | 331383832210022 |