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) |
|---|---|
| 3 | 1 |
| 4 | 16 |
| 5 | 190 |
| 6 | 2024 |
| 7 | 20475 |
| 8 | 201376 |
| 9 | 1947792 |
| 10 | 18643560 |
| 11 | 177232627 |
| 12 | 1677106640 |
| 13 | 15820024220 |
| 14 | 148902215280 |
| 15 | 1399358844975 |
| 16 | 13136858812224 |
| 17 | 123234279768160 |
| 18 | 1155454041309504 |
| 19 | 10830060261901380 |
| 20 | 101489773667796800 |
| 21 | 950974260789566790 |
| 22 | 8910491434304783400 |
| 23 | 83491932238832602485 |