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 | 1 |
| 2 | 3 |
| 3 | 17 |
| 4 | 142 |
| 5 | 1569 |
| 6 | 21576 |
| 7 | 355081 |
| 8 | 6805296 |
| 9 | 148869153 |
| 10 | 3660215680 |
| 11 | 99920609601 |
| 12 | 2998836525312 |
| 13 | 98139640241473 |
| 14 | 3478081490967552 |
| 15 | 132705415800984825 |
| 16 | 5423640496274200576 |
| 17 | 236389784118231290049 |
| 18 | 10944997108429625524224 |
| 19 | 536484538620663729658993 |