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 | 5 |
| 2 | 34 |
| 3 | 258 |
| 4 | 2136 |
| 5 | 19320 |
| 6 | 190800 |
| 7 | 2051280 |
| 8 | 23909760 |
| 9 | 300827520 |
| 10 | 4067884800 |
| 11 | 58877280000 |
| 12 | 908666035200 |
| 13 | 14901260774400 |
| 14 | 258832346572800 |
| 15 | 4748165630208000 |
| 16 | 91746433658880000 |
| 17 | 1862735060938752000 |
| 18 | 39649900359573504000 |
| 19 | 883021783867711488000 |