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 | 3 |
| 3 | 16 |
| 4 | 137 |
| 5 | 1826 |
| 6 | 37777 |
| 7 | 1214256 |
| 8 | 60075185 |
| 9 | 4484316358 |
| 10 | 493489876721 |
| 11 | 78456654767756 |
| 12 | 17735173202222665 |
| 13 | 5630684018989523274 |
| 14 | 2486496790249207981169 |
| 15 | 1515191575312017416011456 |