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 | 72 |
| 4 | 4830 |
| 5 | 39899952 |
| 6 | 6226593544 |
| 7 | 355687354472272 |
| 8 | 121615851757531824 |
| 9 | 25500701524255140352000 |
| 10 | 8839501251731586459279018676600 |
| 11 | 8202317101101304783411826869132800 |
| 12 | 13538116146734258320615004890482768163319520 |
| 13 | 33452526612258948175814325380737291579993833222336 |