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) |
|---|---|
| 5 | 1 |
| 6 | 12 |
| 7 | 90 |
| 8 | 544 |
| 9 | 2907 |
| 10 | 14364 |
| 11 | 67298 |
| 12 | 303600 |
| 13 | 1332045 |
| 14 | 5722860 |
| 15 | 24192090 |
| 16 | 100975680 |
| 17 | 417225900 |
| 18 | 1709984304 |
| 19 | 6962078952 |
| 20 | 28192122176 |
| 21 | 113649492522 |
| 22 | 456442180920 |
| 23 | 1827459250276 |
| 24 | 7297426411968 |
| 25 | 29075683360185 |
| 26 | 115631433392020 |
| 27 | 459124809056550 |
| 28 | 1820529677650320 |
| 29 | 7210477496434485 |