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 | 2 |
| 3 | 1 |
| 4 | 5 |
| 5 | 2 |
| 6 | 20 |
| 7 | 6 |
| 8 | 114 |
| 9 | 24 |
| 10 | 864 |
| 11 | 120 |
| 12 | 8280 |
| 13 | 720 |
| 14 | 96480 |
| 15 | 5040 |
| 16 | 1325520 |
| 17 | 40320 |
| 18 | 20966400 |
| 19 | 362880 |
| 20 | 374855040 |
| 21 | 3628800 |
| 22 | 7468070400 |
| 23 | 39916800 |
| 24 | 163938297600 |
| 25 | 479001600 |
| 26 | 3929729126400 |
| 27 | 6227020800 |
| 28 | 102104460057600 |
| 29 | 87178291200 |
| 30 | 2857878742118400 |
| 31 | 1307674368000 |