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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 9 |
| 6 | 97 |
| 7 | 983 |
| 8 | 10616 |
| 9 | 119932 |
| 10 | 1441405 |
| 11 | 18383351 |
| 12 | 249155667 |
| 13 | 3581896559 |
| 14 | 54540748818 |
| 15 | 877824410030 |
| 16 | 14904605652001 |
| 17 | 266431586957773 |
| 18 | 5004557444810885 |
| 19 | 98594548150006583 |
| 20 | 2033673324306909868 |
| 21 | 43845407809459639440 |
| 22 | 986496730691143433269 |