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 | 2 |
| 3 | 0 |
| 4 | 2 |
| 5 | 6 |
| 6 | 46 |
| 7 | 338 |
| 8 | 2926 |
| 9 | 28146 |
| 10 | 298526 |
| 11 | 3454434 |
| 12 | 43286526 |
| 13 | 583835650 |
| 14 | 8433987582 |
| 15 | 129941213186 |
| 16 | 2127349165822 |
| 17 | 36889047574274 |
| 18 | 675548628690430 |
| 19 | 13030733384956418 |
| 20 | 264111424634864638 |
| 21 | 5612437196153963522 |
| 22 | 124789500579376435198 |
| 23 | 2897684052921851965442 |