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 | 0 |
| 2 | 2 |
| 3 | 14 |
| 4 | 84 |
| 5 | 522 |
| 6 | 3426 |
| 7 | 23404 |
| 8 | 165417 |
| 9 | 1197934 |
| 10 | 8847201 |
| 11 | 66359672 |
| 12 | 504180138 |
| 13 | 3872043674 |
| 14 | 30011312118 |
| 15 | 234460670790 |
| 16 | 1844390161675 |
| 17 | 14597175479270 |
| 18 | 116148990100435 |
| 19 | 928620864502940 |
| 20 | 7456287071153017 |
| 21 | 60101357023288316 |
| 22 | 486144584042042269 |
| 23 | 3944839973878931780 |