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 | 9 |
| 2 | 390 |
| 3 | 20160 |
| 4 | 1106424 |
| 5 | 62606544 |
| 6 | 3611217792 |
| 7 | 211096262400 |
| 8 | 12461757863808 |
| 9 | 741242882016000 |
| 10 | 44355068641175040 |
| 11 | 2667095701669969920 |
| 12 | 161021441731743129600 |
| 13 | 9754428938330096713728 |
| 14 | 592621128107578217201664 |