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 | 1 |
| 3 | 9 |
| 4 | 22 |
| 5 | 77 |
| 6 | 400 |
| 7 | 2624 |
| 8 | 20747 |
| 9 | 183544 |
| 10 | 1826374 |
| 11 | 20045348 |
| 12 | 240262047 |
| 13 | 3120641718 |
| 14 | 43665293393 |
| 15 | 654731266933 |
| 16 | 10472819759734 |
| 17 | 178001257647196 |
| 18 | 3203520381407270 |
| 19 | 60859480965537820 |
| 20 | 1217072840308660049 |