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 | 0 |
| 4 | 10 |
| 5 | 58 |
| 6 | 236 |
| 7 | 836 |
| 8 | 2766 |
| 9 | 8814 |
| 10 | 27472 |
| 11 | 84472 |
| 12 | 257522 |
| 13 | 780770 |
| 14 | 2358708 |
| 15 | 7108908 |
| 16 | 21392278 |
| 17 | 64307926 |
| 18 | 193185944 |
| 19 | 580082144 |
| 20 | 1741295034 |
| 21 | 5225982282 |
| 22 | 15682141180 |
| 23 | 47054812180 |
| 24 | 141181213790 |
| 25 | 423577195838 |
| 26 | 1270798696416 |
| 27 | 3812530307016 |
| 28 | 11437859356546 |
| 29 | 34314114940594 |