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 | 2 |
| 2 | 12 |
| 3 | 68 |
| 4 | 396 |
| 5 | 2358 |
| 6 | 14262 |
| 7 | 87252 |
| 8 | 538440 |
| 9 | 3345434 |
| 10 | 20899816 |
| 11 | 131154264 |
| 12 | 826135794 |
| 13 | 5220372274 |
| 14 | 33077821314 |
| 15 | 210087769632 |
| 16 | 1337104370320 |
| 17 | 8525602760550 |
| 18 | 54449281992528 |
| 19 | 348250972411252 |
| 20 | 2230296171922008 |
| 21 | 14300414859019290 |
| 22 | 91791793780179790 |