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 | -2 |
| 3 | 12 |
| 4 | -6 |
| 5 | -120 |
| 6 | 120 |
| 7 | -24 |
| 8 | 1680 |
| 9 | -2520 |
| 10 | 360 |
| 11 | 720 |
| 12 | -120 |
| 13 | -30240 |
| 14 | 60480 |
| 15 | -20160 |
| 16 | -20160 |
| 17 | 5040 |
| 18 | 5040 |
| 19 | -720 |
| 20 | 665280 |
| 21 | -1663200 |
| 22 | 907200 |
| 23 | 604800 |
| 24 | -60480 |
| 25 | -362880 |
| 26 | -181440 |
| 27 | 20160 |
| 28 | 40320 |
| 29 | 40320 |
| 30 | -5040 |
| 31 | -17297280 |
| 32 | 51891840 |
| 33 | -39916800 |
| 34 | -19958400 |
| 35 | 6652800 |
| 36 | 19958400 |
| 37 | 6652800 |
| 38 | -1814400 |
| 39 | -1814400 |
| 40 | -3628800 |
| 41 | -1814400 |
| 42 | 362880 |
| 43 | 362880 |
| 44 | 362880 |
| 45 | -40320 |