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 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 36 |
| 6 | 142 |
| 7 | 624 |
| 8 | 3192 |
| 9 | 18256 |
| 10 | 116282 |
| 11 | 814144 |
| 12 | 6219972 |
| 13 | 51475776 |
| 14 | 458790022 |
| 15 | 4381112064 |
| 16 | 44625674352 |
| 17 | 482962852096 |
| 18 | 5534347077362 |
| 19 | 66942218896384 |
| 20 | 852334810990332 |
| 21 | 11394877025289216 |
| 22 | 159592488559874302 |
| 23 | 2336793875186479104 |
| 24 | 35703580441464231912 |