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 | 564 |
| 4 | 3298 |
| 5 | 17048 |
| 6 | 80412 |
| 7 | 353485 |
| 8 | 1469903 |
| 9 | 5845411 |
| 10 | 22414731 |
| 11 | 83409546 |
| 12 | 302722400 |
| 13 | 1075880306 |
| 14 | 3756503134 |
| 15 | 12919764299 |
| 16 | 43865509013 |
| 17 | 147290172421 |
| 18 | 489846413077 |
| 19 | 1615582428816 |
| 20 | 5289834522606 |
| 21 | 17210293320924 |
| 22 | 55679866275376 |