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 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 165 |
| 6 | 3465 |
| 7 | 148995 |
| 8 | 12664575 |
| 9 | 2165642325 |
| 10 | 738484032825 |
| 11 | 504384594419475 |
| 12 | 688484971382583375 |
| 13 | 1880252456845835197125 |
| 14 | 10268058666835106011499625 |
| 15 | 112158004817839862963610403875 |