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 | 7 |
| 4 | 19 |
| 5 | 63 |
| 6 | 208 |
| 7 | 802 |
| 8 | 3344 |
| 9 | 15576 |
| 10 | 82368 |
| 11 | 453834 |
| 12 | 2743903 |
| 13 | 17510668 |
| 14 | 114616907 |
| 15 | 785002449 |
| 16 | 5711892439 |
| 17 | 43861741799 |
| 18 | 342522899289 |
| 19 | 2803468693325 |
| 20 | 23621594605383 |
| 21 | 201819398349092 |
| 22 | 1793794228847381 |
| 23 | 16342173067958793 |
| 24 | 154171432351500060 |
| 25 | 1518411003599957803 |