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 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 3 |
| 5 | 5 |
| 6 | 15 |
| 7 | 315 |
| 8 | 630 |
| 9 | 567 |
| 10 | 1134 |
| 11 | 4725 |
| 12 | 9450 |
| 13 | 26325 |
| 14 | 28665 |
| 15 | 116093250 |
| 16 | 116093250 |
| 17 | 7894341000 |
| 18 | 8881133625 |
| 19 | 14849255421000 |
| 20 | 4242644406000 |
| 21 | 3118343638410000 |
| 22 | 3811308891390000 |
| 23 | 34301780022510000 |
| 24 | 205810680135060000 |
| 25 | 1470076286679000000 |
| 26 | 2702564486622000000 |