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 | 2 |
| 4 | 2 |
| 5 | 6 |
| 6 | 2 |
| 7 | 6 |
| 8 | 24 |
| 9 | 4 |
| 10 | 8 |
| 11 | 24 |
| 12 | 120 |
| 13 | 0 |
| 14 | 48 |
| 15 | 24 |
| 16 | 120 |
| 17 | 720 |
| 18 | -120 |
| 19 | 384 |
| 20 | 72 |
| 21 | 144 |
| 22 | 720 |
| 23 | 5040 |
| 24 | -1680 |
| 25 | 3696 |
| 26 | -432 |
| 27 | 1296 |
| 28 | 720 |
| 29 | 5040 |
| 30 | 40320 |
| 31 | -20160 |
| 32 | 40320 |
| 33 | -15840 |
| 34 | 17280 |
| 35 | 2880 |
| 36 | 5760 |
| 37 | 40320 |
| 38 | 362880 |
| 39 | -241920 |
| 40 | 483840 |
| 41 | -311040 |
| 42 | 288000 |
| 43 | -46080 |
| 44 | 69120 |
| 45 | 40320 |