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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 3 |
| 6 | 0 |
| 7 | 1 |
| 8 | 19 |
| 9 | 141 |
| 10 | 394 |
| 11 | 450 |
| 12 | 180 |
| 13 | 0 |
| 14 | 0 |
| 15 | 1 |
| 16 | 306 |
| 17 | 33207 |
| 18 | 921908 |
| 19 | 10359075 |
| 20 | 59584470 |
| 21 | 197644440 |
| 22 | 400752240 |
| 23 | 505197000 |
| 24 | 386694000 |
| 25 | 164656800 |
| 26 | 29937600 |
| 27 | 0 |
| 28 | 0 |
| 29 | 0 |
| 30 | 0 |