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 | 11 |
| 3 | 84 |
| 4 | 598 |
| 5 | 4199 |
| 6 | 29409 |
| 7 | 205882 |
| 8 | 1441196 |
| 9 | 10088397 |
| 10 | 70618807 |
| 11 | 494331680 |
| 12 | 3460321794 |
| 13 | 24222252595 |
| 14 | 169555768205 |
| 15 | 1186890377478 |
| 16 | 8308232642392 |
| 17 | 58157628496793 |
| 18 | 407103399477603 |
| 19 | 2849723796343276 |
| 20 | 19948066574402990 |
| 21 | 139636466020820991 |
| 22 | 977455262145747001 |