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 | 5 |
| 2 | 43 |
| 3 | 374 |
| 4 | 3199 |
| 5 | 26945 |
| 6 | 224296 |
| 7 | 1850672 |
| 8 | 15168751 |
| 9 | 123700631 |
| 10 | 1004849563 |
| 11 | 8137906034 |
| 12 | 65749071892 |
| 13 | 530209766156 |
| 14 | 4269268590280 |
| 15 | 34334967161024 |
| 16 | 275866609658095 |
| 17 | 2214734413345667 |
| 18 | 17769222356447761 |
| 19 | 142492124882039978 |
| 20 | 1142168892887289319 |