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 | 8 |
| 5 | 44 |
| 6 | 208 |
| 7 | 910 |
| 8 | 3808 |
| 9 | 15504 |
| 10 | 62016 |
| 11 | 245157 |
| 12 | 961400 |
| 13 | 3749460 |
| 14 | 14567280 |
| 15 | 56448210 |
| 16 | 218349120 |
| 17 | 843621600 |
| 18 | 3257112960 |
| 19 | 12570420330 |
| 20 | 48507033744 |
| 21 | 187187399448 |
| 22 | 722477682080 |
| 23 | 2789279908316 |
| 24 | 10772391370048 |
| 25 | 41620603020640 |
| 26 | 160878516023680 |
| 27 | 622147386185325 |