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) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 180 |
| 4 | 4890 |
| 5 | 36028 |
| 6 | 154434 |
| 7 | 488660 |
| 8 | 1271450 |
| 9 | 2883900 |
| 10 | 5907298 |
| 11 | 11182644 |
| 12 | 19877850 |
| 13 | 33562620 |
| 14 | 54291010 |
| 15 | 84691668 |
| 16 | 128065754 |
| 17 | 188492540 |
| 18 | 270942690 |
| 19 | 381399220 |
| 20 | 526986138 |
| 21 | 716104764 |
| 22 | 958577730 |
| 23 | 1265800660 |
| 24 | 1650901530 |
| 25 | 2128907708 |
| 26 | 2716920674 |
| 27 | 3434298420 |