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 | 3 |
| 3 | 16 |
| 4 | 71 |
| 5 | 345 |
| 6 | 1624 |
| 7 | 17121 |
| 8 | 71577 |
| 9 | 345342 |
| 10 | 1624171 |
| 11 | 17121011 |
| 12 | 71577060 |
| 13 | 345342131 |
| 14 | 1624173733 |
| 15 | 17331156576 |
| 16 | 71473314601 |
| 17 | 345325637555 |
| 18 | 3624144315044 |
| 19 | 16333160460471 |
| 20 | 71272765314407 |