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 | 2 |
| 4 | 5 |
| 5 | 26 |
| 6 | 261 |
| 7 | 3216 |
| 8 | 19617 |
| 9 | 80860 |
| 10 | 262651 |
| 11 | 737716 |
| 12 | 1920821 |
| 13 | 5013152 |
| 14 | 14277485 |
| 15 | 47610876 |
| 16 | 186355041 |
| 17 | 820625616 |
| 18 | 3869589607 |
| 19 | 19039193980 |
| 20 | 96332399701 |
| 21 | 499138921736 |
| 22 | 2639262062801 |
| 23 | 14234781051932 |
| 24 | 78188865206145 |
| 25 | 437305612997376 |
| 26 | 2487692697142251 |