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 | 5 |
| 4 | -1 |
| 5 | 12 |
| 6 | -32 |
| 7 | -1 |
| 8 | 14 |
| 9 | 7 |
| 10 | -126 |
| 11 | 231 |
| 12 | -1 |
| 13 | 16 |
| 14 | 16 |
| 15 | -160 |
| 16 | -160 |
| 17 | 1280 |
| 18 | -1792 |
| 19 | -1 |
| 20 | 18 |
| 21 | 18 |
| 22 | -198 |
| 23 | 9 |
| 24 | -396 |
| 25 | 1716 |
| 26 | -66 |
| 27 | 2574 |
| 28 | -12870 |
| 29 | 14586 |
| 30 | -1 |
| 31 | 20 |
| 32 | 20 |
| 33 | -240 |
| 34 | 20 |
| 35 | -480 |
| 36 | 2240 |
| 37 | -240 |
| 38 | -240 |
| 39 | 6720 |
| 40 | -17920 |
| 41 | 2240 |
| 42 | -35840 |
| 43 | 129024 |
| 44 | -122880 |
| 45 | -1 |
| 46 | 22 |
| 47 | 22 |
| 48 | -286 |
| 49 | 22 |
| 50 | -572 |
| 51 | 2860 |
| 52 | 11 |
| 53 | -572 |
| 54 | -286 |
| 55 | 8580 |
| 56 | -24310 |
| 57 | -286 |
| 58 | 4290 |
| 59 | 8580 |
| 60 | -97240 |
| 61 | 184756 |
| 62 | 715 |