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 | 3 |
| 2 | 3 |
| 3 | -1 |
| 4 | -6 |
| 5 | -6 |
| 6 | 1 |
| 7 | 9 |
| 8 | 9 |
| 9 | -1 |
| 10 | -12 |
| 11 | -12 |
| 12 | 1 |
| 13 | 15 |
| 14 | 15 |
| 15 | -1 |
| 16 | -18 |
| 17 | -18 |
| 18 | 1 |
| 19 | 21 |
| 20 | 21 |
| 21 | -1 |
| 22 | -24 |
| 23 | -24 |
| 24 | 1 |
| 25 | 27 |
| 26 | 27 |
| 27 | -1 |
| 28 | -30 |
| 29 | -30 |
| 30 | 1 |
| 31 | 33 |
| 32 | 33 |
| 33 | -1 |
| 34 | -36 |
| 35 | -36 |
| 36 | 1 |
| 37 | 39 |
| 38 | 39 |
| 39 | -1 |
| 40 | -42 |
| 41 | -42 |
| 42 | 1 |
| 43 | 45 |
| 44 | 45 |
| 45 | -1 |
| 46 | -48 |
| 47 | -48 |
| 48 | 1 |
| 49 | 51 |
| 50 | 51 |
| 51 | -1 |
| 52 | -54 |
| 53 | -54 |
| 54 | 1 |
| 55 | 57 |
| 56 | 57 |
| 57 | -1 |
| 58 | -60 |
| 59 | -60 |
| 60 | 1 |