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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 9 |
| 7 | 23 |
| 8 | 62 |
| 9 | 176 |
| 10 | 512 |
| 11 | 1551 |
| 12 | 4822 |
| 13 | 15266 |
| 14 | 49141 |
| 15 | 160728 |
| 16 | 532890 |
| 17 | 1785162 |
| 18 | 6039328 |
| 19 | 20617808 |
| 20 | 70951548 |
| 21 | 245911020 |
| 22 | 857888714 |
| 23 | 3010811846 |
| 24 | 10624583264 |
| 25 | 37680980256 |
| 26 | 134260382400 |
| 27 | 480440869030 |
| 28 | 1726092837412 |
| 29 | 6224442777366 |
| 30 | 22523780202156 |