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 | 1 |
| 4 | 4 |
| 5 | -5 |
| 6 | 1 |
| 7 | -36 |
| 8 | 49 |
| 9 | -14 |
| 10 | 1 |
| 11 | 576 |
| 12 | -820 |
| 13 | 273 |
| 14 | -30 |
| 15 | 1 |
| 16 | -14400 |
| 17 | 21076 |
| 18 | -7645 |
| 19 | 1023 |
| 20 | -55 |
| 21 | 1 |
| 22 | 518400 |
| 23 | -773136 |
| 24 | 296296 |
| 25 | -44473 |
| 26 | 3003 |
| 27 | -91 |
| 28 | 1 |
| 29 | -25401600 |
| 30 | 38402064 |
| 31 | -15291640 |
| 32 | 2475473 |
| 33 | -191620 |
| 34 | 7462 |
| 35 | -140 |
| 36 | 1 |
| 37 | 1625702400 |
| 38 | -2483133696 |
| 39 | 1017067024 |
| 40 | -173721912 |
| 41 | 14739153 |
| 42 | -669188 |
| 43 | 16422 |
| 44 | -204 |
| 45 | 1 |