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 | 6 |
| 2 | 78 |
| 3 | 804 |
| 4 | 8316 |
| 5 | 85176 |
| 6 | 1021608 |
| 7 | 11394432 |
| 8 | 144885888 |
| 9 | 1886008320 |
| 10 | 26529503616 |
| 11 | 390680672256 |
| 12 | 6237490904064 |
| 13 | 104348756736000 |
| 14 | 1873079661358080 |
| 15 | 35428981499412480 |
| 16 | 710916534432276480 |
| 17 | 14999585506406645760 |
| 18 | 333292875250857984000 |
| 19 | 7754472236069830656000 |