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 | 3 |
| 2 | 15 |
| 3 | 118 |
| 4 | 1125 |
| 5 | 11805 |
| 6 | 131431 |
| 7 | 1524090 |
| 8 | 18208749 |
| 9 | 222570985 |
| 10 | 2770129627 |
| 11 | 34985756752 |
| 12 | 447243818573 |
| 13 | 5775955923428 |
| 14 | 75245253495035 |
| 15 | 987627627396792 |
| 16 | 13048147674230169 |
| 17 | 173382031819242855 |
| 18 | 2315662483861709467 |
| 19 | 31068798980975635130 |
| 20 | 418552735866147739185 |