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 | 1 |
| 5 | 21 |
| 6 | 161 |
| 7 | 813 |
| 8 | 3361 |
| 9 | 12421 |
| 10 | 42865 |
| 11 | 141549 |
| 12 | 453905 |
| 13 | 1426725 |
| 14 | 4422913 |
| 15 | 13579309 |
| 16 | 41408833 |
| 17 | 125667333 |
| 18 | 380081105 |
| 19 | 1146795693 |
| 20 | 3454279345 |
| 21 | 10392196645 |
| 22 | 31238454241 |
| 23 | 93845384301 |
| 24 | 281808780641 |
| 25 | 845996765061 |
| 26 | 2539181475121 |
| 27 | 7620027450733 |
| 28 | 22865249731921 |