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) |
|---|---|
| 3 | 5 |
| 4 | 23 |
| 5 | 95 |
| 6 | 719 |
| 7 | 5039 |
| 8 | 39917 |
| 9 | 361657 |
| 10 | 3624941 |
| 11 | 39904153 |
| 12 | 479001599 |
| 13 | 6226862869 |
| 14 | 87178291199 |
| 15 | 1307672080867 |
| 16 | 20922780738961 |
| 17 | 355687390376431 |
| 18 | 6402373545694717 |
| 19 | 121645099711277873 |
| 20 | 2432902005056589697 |
| 21 | 51090942157413850441 |