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) |
|---|---|
| 5 | 1 |
| 6 | 12 |
| 7 | 91 |
| 8 | 560 |
| 9 | 3060 |
| 10 | 15504 |
| 11 | 74613 |
| 12 | 346104 |
| 13 | 1562275 |
| 14 | 6906900 |
| 15 | 30045015 |
| 16 | 129024480 |
| 17 | 548354040 |
| 18 | 2310789600 |
| 19 | 9669554100 |
| 20 | 40225345056 |
| 21 | 166509721602 |
| 22 | 686353797976 |
| 23 | 2818953098830 |
| 24 | 11541847896480 |
| 25 | 47129212243960 |
| 26 | 191991813933920 |
| 27 | 780512175396135 |
| 28 | 3167295784216200 |