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 | 1 |
| 3 | 12 |
| 4 | 30 |
| 5 | 20 |
| 6 | 1 |
| 7 | 60 |
| 8 | 690 |
| 9 | 2940 |
| 10 | 5670 |
| 11 | 5040 |
| 12 | 1680 |
| 13 | 1 |
| 14 | 252 |
| 15 | 8730 |
| 16 | 103820 |
| 17 | 581700 |
| 18 | 1767360 |
| 19 | 3087000 |
| 20 | 3099600 |
| 21 | 1663200 |
| 22 | 369600 |
| 23 | 1 |
| 24 | 1020 |
| 25 | 94890 |
| 26 | 2615340 |
| 27 | 32186070 |
| 28 | 214628400 |
| 29 | 859992000 |
| 30 | 2189325600 |
| 31 | 3628409400 |
| 32 | 3903900000 |
| 33 | 2630628000 |
| 34 | 1009008000 |
| 35 | 168168000 |
| 36 | 1 |
| 37 | 4092 |
| 38 | 979530 |
| 39 | 58061420 |
| 40 | 1411122300 |