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 | 0 |
| 4 | 2 |
| 5 | 10 |
| 6 | 0 |
| 7 | 0 |
| 8 | 4 |
| 9 | 32 |
| 10 | 76 |
| 11 | 196 |
| 12 | 632 |
| 13 | 3368 |
| 14 | 12532 |
| 15 | 79788 |
| 16 | 468286 |
| 17 | 2815088 |
| 18 | 18287968 |
| 19 | 126620984 |
| 20 | 938037664 |
| 21 | 7232141830 |
| 22 | 59774887344 |