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) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 108 |
| 3 | 1488 |
| 4 | 22230 |
| 5 | 350244 |
| 6 | 5729724 |
| 7 | 96395616 |
| 8 | 1657248417 |
| 9 | 28987537150 |
| 10 | 514215324216 |
| 11 | 9229030737264 |
| 12 | 167283594343320 |
| 13 | 3057857090083908 |
| 14 | 56305821384711720 |
| 15 | 1043424549990820800 |
| 16 | 19445145508444588200 |
| 17 | 364191559218548917713 |
| 18 | 6851518654436447733980 |