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 | 17 |
| 4 | 106 |
| 5 | 693 |
| 6 | 4690 |
| 7 | 32754 |
| 8 | 234746 |
| 9 | 1719325 |
| 10 | 12820920 |
| 11 | 97039824 |
| 12 | 743680508 |
| 13 | 5759507657 |
| 14 | 45006692668 |
| 15 | 354425763797 |
| 16 | 2809931206626 |
| 17 | 22409524536076 |
| 18 | 179655903886571 |
| 19 | 1447023307374888 |
| 20 | 11703779855021636 |
| 21 | 95020085240320710 |
| 22 | 774088021528328920 |