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 | 0 |
| 1 | 2 |
| 2 | 40 |
| 3 | 402 |
| 4 | 2720 |
| 5 | 14002 |
| 6 | 58728 |
| 7 | 209762 |
| 8 | 658048 |
| 9 | 1854882 |
| 10 | 4780008 |
| 11 | 11414898 |
| 12 | 25534368 |
| 13 | 53972178 |
| 14 | 108568488 |
| 15 | 209070018 |
| 16 | 387328512 |
| 17 | 693230658 |
| 18 | 1202893992 |
| 19 | 2029779538 |
| 20 | 3339504032 |
| 21 | 5369283570 |
| 22 | 8453107432 |
| 23 | 13053926690 |
| 24 | 19804348032 |
| 25 | 29557550050 |
| 26 | 43450388072 |