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) |
|---|---|
| 4 | 0 |
| 5 | 1 |
| 6 | 6 |
| 7 | 35 |
| 8 | 168 |
| 9 | 807 |
| 10 | 3738 |
| 11 | 17326 |
| 12 | 79909 |
| 13 | 369330 |
| 14 | 1709087 |
| 15 | 7929590 |
| 16 | 36880231 |
| 17 | 171981241 |
| 18 | 804008476 |
| 19 | 3767969067 |
| 20 | 17699758030 |
| 21 | 83328230588 |
| 22 | 393123455667 |
| 23 | 1858351021018 |
| 24 | 8801159427825 |
| 25 | 41756067216508 |
| 26 | 198437454009869 |
| 27 | 944521139813575 |
| 28 | 4502419756667924 |