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 | 9 |
| 2 | 49 |
| 3 | 249 |
| 4 | 1249 |
| 5 | 18751 |
| 6 | 218751 |
| 7 | 781249 |
| 8 | 24218751 |
| 9 | 74218751 |
| 10 | 1425781249 |
| 11 | 13574218751 |
| 12 | 163574218751 |
| 13 | 163574218751 |
| 14 | 19836425781249 |
| 15 | 19836425781249 |
| 16 | 2480163574218751 |
| 17 | 12519836425781249 |
| 18 | 12519836425781249 |
| 19 | 487480163574218751 |
| 20 | 15487480163574218751 |
| 21 | 215487480163574218751 |
| 22 | 215487480163574218751 |