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 | 3 |
| 3 | 14 |
| 4 | 65 |
| 5 | 448 |
| 6 | 3136 |
| 7 | 32028 |
| 8 | 251922 |
| 9 | 2891801 |
| 10 | 30684797 |
| 11 | 464651863 |
| 12 | 5434037232 |
| 13 | 92246217970 |
| 14 | 1379368317328 |
| 15 | 29135744093948 |
| 16 | 414052904722966 |
| 17 | 8546218817446727 |
| 18 | 152935671938144301 |
| 19 | 3857215760145872627 |
| 20 | 70913916905782150177 |
| 21 | 1881992311219764068420 |