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 | 2 |
| 2 | 1 |
| 3 | 4 |
| 4 | 9 |
| 5 | 30 |
| 6 | 97 |
| 7 | 373 |
| 8 | 1405 |
| 9 | 5630 |
| 10 | 22672 |
| 11 | 93045 |
| 12 | 384403 |
| 13 | 1602156 |
| 14 | 6712128 |
| 15 | 28268504 |
| 16 | 119537113 |
| 17 | 507375130 |
| 18 | 2160476897 |
| 19 | 9226446455 |
| 20 | 39504435891 |