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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 12 |
| 6 | 54 |
| 7 | 147 |
| 8 | 593 |
| 9 | 1886 |
| 10 | 7292 |
| 11 | 25204 |
| 12 | 96153 |
| 13 | 348304 |
| 14 | 1327716 |
| 15 | 4946471 |
| 16 | 18936366 |
| 17 | 71827598 |
| 18 | 276612103 |
| 19 | 1062220253 |
| 20 | 4115807184 |
| 21 | 15947902376 |
| 22 | 62148513732 |
| 23 | 242485933208 |
| 24 | 949828266722 |
| 25 | 3726623622402 |
| 26 | 14663689944397 |
| 27 | 57798199213989 |