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 | 0 |
| 1 | 1 |
| 2 | 11 |
| 3 | 100 |
| 4 | 891 |
| 5 | 7921 |
| 6 | 70400 |
| 7 | 625681 |
| 8 | 5560731 |
| 9 | 49420900 |
| 10 | 439227371 |
| 11 | 3903625441 |
| 12 | 34693401600 |
| 13 | 308336988961 |
| 14 | 2740339499051 |
| 15 | 24354718502500 |
| 16 | 216452127023451 |
| 17 | 1923714424708561 |
| 18 | 17096977695353600 |
| 19 | 151949084833473841 |