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 | 1 |
| 3 | 2 |
| 4 | 1 |
| 5 | -1 |
| 6 | 6 |
| 7 | 1 |
| 8 | -4 |
| 9 | 1 |
| 10 | 24 |
| 11 | -2 |
| 12 | -17 |
| 13 | 8 |
| 14 | -1 |
| 15 | 120 |
| 16 | -34 |
| 17 | -83 |
| 18 | 57 |
| 19 | -13 |
| 20 | 1 |
| 21 | 720 |
| 22 | -324 |
| 23 | -464 |
| 24 | 425 |
| 25 | -135 |
| 26 | 19 |
| 27 | -1 |
| 28 | 5040 |
| 29 | -2988 |
| 30 | -2924 |
| 31 | 3439 |
| 32 | -1370 |
| 33 | 268 |
| 34 | -26 |
| 35 | 1 |
| 36 | 40320 |
| 37 | -28944 |
| 38 | -20404 |
| 39 | 30436 |
| 40 | -14399 |
| 41 | 3514 |
| 42 | -476 |
| 43 | 34 |
| 44 | -1 |
| 45 | 362880 |
| 46 | -300816 |
| 47 | -154692 |
| 48 | 294328 |
| 49 | -160027 |
| 50 | 46025 |
| 51 | -7798 |
| 52 | 782 |
| 53 | -43 |
| 54 | 1 |