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 | 1 |
| 5 | -3 |
| 6 | 2 |
| 7 | 1 |
| 8 | -4 |
| 9 | -3 |
| 10 | 12 |
| 11 | -6 |
| 12 | 1 |
| 13 | -5 |
| 14 | -10 |
| 15 | 20 |
| 16 | 30 |
| 17 | -60 |
| 18 | 24 |
| 19 | 1 |
| 20 | -6 |
| 21 | -15 |
| 22 | -10 |
| 23 | 30 |
| 24 | 120 |
| 25 | 30 |
| 26 | -120 |
| 27 | -270 |
| 28 | 360 |
| 29 | -120 |
| 30 | 1 |
| 31 | -7 |
| 32 | -21 |
| 33 | -35 |
| 34 | 42 |
| 35 | 210 |
| 36 | 140 |
| 37 | 210 |
| 38 | -210 |
| 39 | -1260 |
| 40 | -630 |
| 41 | 840 |
| 42 | 2520 |
| 43 | -2520 |
| 44 | 720 |
| 45 | 1 |
| 46 | -8 |
| 47 | -28 |
| 48 | -56 |
| 49 | -35 |
| 50 | 56 |
| 51 | 336 |
| 52 | 560 |
| 53 | 420 |
| 54 | 560 |
| 55 | -336 |
| 56 | -2520 |
| 57 | -1680 |
| 58 | -5040 |
| 59 | -630 |
| 60 | 1680 |
| 61 | 13440 |
| 62 | 10080 |
| 63 | -6720 |