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 | 15 |
| 4 | 184 |
| 5 | 3145 |
| 6 | 68976 |
| 7 | 1846999 |
| 8 | 58413440 |
| 9 | 2130740721 |
| 10 | 88061420800 |
| 11 | 4066862460991 |
| 12 | 207556068584448 |
| 13 | 11600364266112505 |
| 14 | 704664527894104064 |
| 15 | 46226086991634882375 |
| 16 | 3256882066245640093696 |
| 17 | 245279323467051422886241 |