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) |
|---|---|
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 12 |
| 7 | 33 |
| 8 | 102 |
| 9 | 312 |
| 10 | 1010 |
| 11 | 3256 |
| 12 | 10836 |
| 13 | 36094 |
| 14 | 122544 |
| 15 | 417150 |
| 16 | 1437712 |
| 17 | 4970904 |
| 18 | 17333772 |
| 19 | 60638124 |
| 20 | 213435264 |
| 21 | 753520804 |
| 22 | 2672606464 |
| 23 | 9505230397 |
| 24 | 33928264990 |
| 25 | 121400935184 |
| 26 | 435660446342 |
| 27 | 1566809204928 |
| 28 | 5648450745204 |
| 29 | 20402191885146 |
| 30 | 73842311224632 |