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 | 3 |
| 3 | 25 |
| 4 | 543 |
| 5 | 29281 |
| 6 | 3781503 |
| 7 | 1138779265 |
| 8 | 783702329343 |
| 9 | 1213442454842881 |
| 10 | 4175098976430598143 |
| 11 | 31603459396418917607425 |
| 12 | 521939651343829405020504063 |
| 13 | 18676600744432035186664816926721 |
| 14 | 1439428141044398334941790719839535103 |
| 15 | 237725265553410354992180218286376719253505 |