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 | 8 |
| 2 | 52 |
| 3 | 272 |
| 4 | 1274 |
| 5 | 5408 |
| 6 | 21448 |
| 7 | 80080 |
| 8 | 285043 |
| 9 | 972496 |
| 10 | 3200644 |
| 11 | 10199456 |
| 12 | 31592350 |
| 13 | 95366176 |
| 14 | 281269560 |
| 15 | 812094448 |
| 16 | 2299480441 |
| 17 | 6394796832 |
| 18 | 17489643664 |
| 19 | 47096042032 |
| 20 | 124993380566 |
| 21 | 327249781952 |