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 | 1 |
| 4 | 1 |
| 5 | 601 |
| 6 | 4321 |
| 7 | 17641 |
| 8 | 53761 |
| 9 | 136081 |
| 10 | 181742401 |
| 11 | 2415576241 |
| 12 | 17245198081 |
| 13 | 87699217321 |
| 14 | 355981385761 |
| 15 | 736792782125401 |
| 16 | 14287010845685761 |
| 17 | 145634558983324321 |
| 18 | 1037210264169367681 |
| 19 | 5794253172081059041 |
| 20 | 16246379099801447769601 |