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) |
|---|---|
| 2 | 1 |
| 3 | 21 |
| 4 | 294 |
| 5 | 3430 |
| 6 | 36015 |
| 7 | 352947 |
| 8 | 3294172 |
| 9 | 29647548 |
| 10 | 259416045 |
| 11 | 2219448385 |
| 12 | 18643366434 |
| 13 | 154231485954 |
| 14 | 1259557135291 |
| 15 | 10173346092735 |
| 16 | 81386768741880 |
| 17 | 645668365352248 |
| 18 | 5084638377148953 |
| 19 | 39779817891812397 |
| 20 | 309398583602985310 |