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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 11 |
| 5 | 40 |
| 6 | 166 |
| 7 | 658 |
| 8 | 2647 |
| 9 | 10592 |
| 10 | 42446 |
| 11 | 169972 |
| 12 | 680670 |
| 13 | 2725320 |
| 14 | 10910992 |
| 15 | 43678882 |
| 16 | 174843151 |
| 17 | 699839680 |
| 18 | 2801078662 |
| 19 | 11210671612 |
| 20 | 44866276906 |
| 21 | 179552951440 |
| 22 | 718539964132 |
| 23 | 2875389341332 |
| 24 | 11506176209206 |
| 25 | 46042099714240 |
| 26 | 184234059839116 |
| 27 | 737184620655368 |