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 | 5 |
| 4 | 16 |
| 5 | 67 |
| 6 | 368 |
| 7 | 2630 |
| 8 | 24376 |
| 9 | 293770 |
| 10 | 4610624 |
| 11 | 94080653 |
| 12 | 2492747656 |
| 13 | 85827875506 |
| 14 | 3842929319936 |
| 15 | 223624506056156 |
| 16 | 16901839470598576 |
| 17 | 1659776507866213636 |
| 18 | 211853506422044996288 |
| 19 | 35137231473111223912310 |
| 20 | 7569998079873075147860464 |