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 | 0 |
| 1 | 1 |
| 2 | 13 |
| 3 | 146 |
| 4 | 1650 |
| 5 | 19524 |
| 6 | 245004 |
| 7 | 3272688 |
| 8 | 46536624 |
| 9 | 703404576 |
| 10 | 11277554400 |
| 11 | 191338156800 |
| 12 | 3427105248000 |
| 13 | 64651956364800 |
| 14 | 1281740285145600 |
| 15 | 26648514872985600 |
| 16 | 579892995734169600 |
| 17 | 13183403757582643200 |