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) |
|---|---|
| 2 | 1 |
| 3 | 16 |
| 4 | 114 |
| 5 | 644 |
| 6 | 3270 |
| 7 | 15642 |
| 8 | 72072 |
| 9 | 323752 |
| 10 | 1428102 |
| 11 | 6214520 |
| 12 | 26761196 |
| 13 | 114287736 |
| 14 | 484816540 |
| 15 | 2045277990 |
| 16 | 8588492100 |
| 17 | 35923392720 |
| 18 | 149753379270 |
| 19 | 622458753840 |
| 20 | 2580709189740 |
| 21 | 10675646755800 |
| 22 | 44074384410420 |
| 23 | 181638630107220 |
| 24 | 747375951913344 |
| 25 | 3070765657798704 |