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 | 5 |
| 3 | 21 |
| 4 | 87 |
| 5 | 378 |
| 6 | 1682 |
| 7 | 7596 |
| 8 | 34688 |
| 9 | 159724 |
| 10 | 740243 |
| 11 | 3448579 |
| 12 | 16134813 |
| 13 | 75760294 |
| 14 | 356811308 |
| 15 | 1684882778 |
| 16 | 7974184903 |
| 17 | 37815280813 |
| 18 | 179644013528 |
| 19 | 854749753320 |
| 20 | 4072634928710 |
| 21 | 19429522879905 |
| 22 | 92799859650401 |