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) |
|---|---|
| 1 | 1 |
| 2 | 10 |
| 3 | 63 |
| 4 | 324 |
| 5 | 1485 |
| 6 | 6318 |
| 7 | 25515 |
| 8 | 99144 |
| 9 | 373977 |
| 10 | 1377810 |
| 11 | 4979799 |
| 12 | 17714700 |
| 13 | 62178597 |
| 14 | 215765046 |
| 15 | 741360195 |
| 16 | 2525407632 |
| 17 | 8537599665 |
| 18 | 28669116186 |
| 19 | 95692860783 |
| 20 | 317684800980 |
| 21 | 1049522104701 |
| 22 | 3451916556990 |
| 23 | 11307641812443 |