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) |
|---|---|
| 1 | 5 |
| 2 | 17 |
| 3 | 41 |
| 4 | 257 |
| 5 | 521 |
| 6 | 4481 |
| 7 | 9521 |
| 8 | 21929 |
| 9 | 72089 |
| 10 | 531977 |
| 11 | 1256009 |
| 12 | 5014169 |
| 13 | 20879129 |
| 14 | 70993529 |
| 15 | 258844361 |
| 16 | 866941841 |
| 17 | 3771185921 |
| 18 | 13949589209 |
| 19 | 57388297721 |