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 | 1 |
| 4 | 1 |
| 5 | -2 |
| 6 | 1 |
| 7 | -2 |
| 8 | -5 |
| 9 | 6 |
| 10 | 1 |
| 11 | 2 |
| 12 | -13 |
| 13 | -14 |
| 14 | 24 |
| 15 | 1 |
| 16 | -3 |
| 17 | -23 |
| 18 | 51 |
| 19 | 94 |
| 20 | -120 |
| 21 | 1 |
| 22 | 3 |
| 23 | -41 |
| 24 | -87 |
| 25 | 400 |
| 26 | 444 |
| 27 | -720 |
| 28 | 1 |
| 29 | -4 |
| 30 | -62 |
| 31 | 200 |
| 32 | 1009 |
| 33 | -2356 |
| 34 | -3828 |
| 35 | 5040 |
| 36 | 1 |
| 37 | 4 |
| 38 | -94 |
| 39 | -296 |
| 40 | 2609 |
| 41 | 5716 |
| 42 | -22676 |
| 43 | -25584 |
| 44 | 40320 |
| 45 | 1 |
| 46 | -5 |
| 47 | -130 |
| 48 | 550 |
| 49 | 5273 |
| 50 | -17765 |
| 51 | -74120 |
| 52 | 178500 |
| 53 | 270576 |
| 54 | -362880 |