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) |
|---|---|
| 2 | 1 |
| 3 | 6 |
| 4 | 32 |
| 5 | 136 |
| 6 | 640 |
| 7 | 2593 |
| 8 | 11860 |
| 9 | 47532 |
| 10 | 215531 |
| 11 | 861334 |
| 12 | 3893621 |
| 13 | 15549166 |
| 14 | 70199065 |
| 15 | 280316029 |
| 16 | 1264697307 |
| 17 | 5050617474 |
| 18 | 22776900816 |
| 19 | 90972831448 |
| 20 | 410117333080 |