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) |
|---|---|
| 4 | 1 |
| 5 | 76 |
| 6 | 1682 |
| 7 | 23548 |
| 8 | 259723 |
| 9 | 2485288 |
| 10 | 21707972 |
| 11 | 178300904 |
| 12 | 1403080725 |
| 13 | 10708911188 |
| 14 | 79944249686 |
| 15 | 587172549764 |
| 16 | 4261002128223 |
| 17 | 30644790782352 |
| 18 | 218917362275080 |
| 19 | 1556000598766224 |
| 20 | 11017646288488233 |
| 21 | 77790282457881756 |