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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 171 |
| 7 | 17066 |
| 8 | 1298346 |
| 9 | 83384427 |
| 10 | 4762648737 |
| 11 | 249485204452 |
| 12 | 12226539786912 |
| 13 | 568267449522773 |
| 14 | 25296121946918823 |
| 15 | 1086375882592194558 |
| 16 | 45264846407024660598 |
| 17 | 1837809636559394481439 |
| 18 | 72965749033508656346829 |