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 | 81 |
| 3 | 271 |
| 4 | 1307 |
| 5 | 5369 |
| 6 | 23645 |
| 7 | 101233 |
| 8 | 439063 |
| 9 | 1893511 |
| 10 | 8183735 |
| 11 | 35331965 |
| 12 | 152610763 |
| 13 | 659074589 |
| 14 | 2846603441 |
| 15 | 12294305751 |
| 16 | 53098868971 |
| 17 | 229330454403 |
| 18 | 990464516749 |
| 19 | 4277755155395 |
| 20 | 18475391521815 |
| 21 | 79794234969705 |