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 | 0 |
| 2 | 42 |
| 3 | 222 |
| 4 | 1764 |
| 5 | 12458 |
| 6 | 90684 |
| 7 | 654864 |
| 8 | 4738970 |
| 9 | 34274630 |
| 10 | 247928860 |
| 11 | 1793345580 |
| 12 | 12971955294 |
| 13 | 93830864024 |
| 14 | 678713206224 |
| 15 | 4909381705850 |
| 16 | 35511361462492 |
| 17 | 256866719859442 |
| 18 | 1858011331955384 |
| 19 | 13439678399558656 |
| 20 | 97214130194552336 |