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 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 50 |
| 4 | 288 |
| 5 | 1605 |
| 6 | 8824 |
| 7 | 48286 |
| 8 | 264128 |
| 9 | 1447338 |
| 10 | 7953040 |
| 11 | 43842788 |
| 12 | 242507456 |
| 13 | 1345868589 |
| 14 | 7493458392 |
| 15 | 41850173670 |
| 16 | 234408444288 |
| 17 | 1316541032958 |
| 18 | 7413214297968 |
| 19 | 41842633282620 |
| 20 | 236703844320960 |