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 | 3 |
| 2 | -1 |
| 3 | 20 |
| 4 | -10 |
| 5 | 1 |
| 6 | 210 |
| 7 | -126 |
| 8 | 21 |
| 9 | -1 |
| 10 | 3024 |
| 11 | -2016 |
| 12 | 432 |
| 13 | -36 |
| 14 | 1 |
| 15 | 55440 |
| 16 | -39600 |
| 17 | 9900 |
| 18 | -1100 |
| 19 | 55 |
| 20 | -1 |
| 21 | 1235520 |
| 22 | -926640 |
| 23 | 257400 |
| 24 | -34320 |
| 25 | 2340 |
| 26 | -78 |
| 27 | 1 |
| 28 | 32432400 |
| 29 | -25225200 |
| 30 | 7567560 |
| 31 | -1146600 |
| 32 | 95550 |
| 33 | -4410 |
| 34 | 105 |
| 35 | -1 |
| 36 | 980179200 |
| 37 | -784143360 |
| 38 | 249500160 |
| 39 | -41583360 |
| 40 | 3998400 |
| 41 | -228480 |
| 42 | 7616 |
| 43 | -136 |
| 44 | 1 |