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 | 3 |
| 3 | 26 |
| 4 | 252 |
| 5 | 3124 |
| 6 | 46626 |
| 7 | 823542 |
| 8 | 16776960 |
| 9 | 387420462 |
| 10 | 9999996872 |
| 11 | 285311670610 |
| 12 | 8916100401348 |
| 13 | 302875106592252 |
| 14 | 11112006824734470 |
| 15 | 437893890380856224 |
| 16 | 18446744073692774400 |
| 17 | 827240261886336764176 |