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 | 3 |
| 4 | 13 |
| 5 | 69 |
| 6 | 396 |
| 7 | 2355 |
| 8 | 14363 |
| 9 | 89706 |
| 10 | 573828 |
| 11 | 3758866 |
| 12 | 25195016 |
| 13 | 172591294 |
| 14 | 1206482317 |
| 15 | 8592827996 |
| 16 | 62257890162 |
| 17 | 458214977642 |
| 18 | 3421294482237 |
| 19 | 25884913987768 |
| 20 | 198236423171483 |
| 21 | 1535315006313002 |
| 22 | 12015208271571543 |
| 23 | 94943908405295171 |
| 24 | 757044806198966152 |