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 | 5 |
| 2 | -1 |
| 3 | 30 |
| 4 | -12 |
| 5 | 1 |
| 6 | 210 |
| 7 | -126 |
| 8 | 21 |
| 9 | -1 |
| 10 | 1680 |
| 11 | -1344 |
| 12 | 336 |
| 13 | -32 |
| 14 | 1 |
| 15 | 15120 |
| 16 | -15120 |
| 17 | 5040 |
| 18 | -720 |
| 19 | 45 |
| 20 | -1 |
| 21 | 151200 |
| 22 | -181440 |
| 23 | 75600 |
| 24 | -14400 |
| 25 | 1350 |
| 26 | -60 |
| 27 | 1 |
| 28 | 1663200 |
| 29 | -2328480 |
| 30 | 1164240 |
| 31 | -277200 |
| 32 | 34650 |
| 33 | -2310 |
| 34 | 77 |
| 35 | -1 |
| 36 | 19958400 |
| 37 | -31933440 |