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 | 0 |
| 2 | 3 |
| 3 | 75 |
| 4 | 3108 |
| 5 | 205125 |
| 6 | 19839633 |
| 7 | 2643131400 |
| 8 | 463873573803 |
| 9 | 103710628476075 |
| 10 | 28775903316814668 |
| 11 | 9702563010998171325 |
| 12 | 3907429085273025561153 |
| 13 | 1852516229654506870381200 |
| 14 | 1021325008815288529961197683 |
| 15 | 647900078249178232882473232875 |