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 | 10 |
| 2 | 60 |
| 3 | 340 |
| 4 | 1920 |
| 5 | 10900 |
| 6 | 62280 |
| 7 | 358060 |
| 8 | 2070240 |
| 9 | 12030820 |
| 10 | 70231800 |
| 11 | 411625180 |
| 12 | 2420922960 |
| 13 | 14281397140 |
| 14 | 84467679720 |
| 15 | 500702562700 |
| 16 | 2973697798080 |
| 17 | 17689598897860 |
| 18 | 105374653934040 |
| 19 | 628433226338620 |