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 | 0 |
| 2 | -1 |
| 3 | 4 |
| 4 | 9 |
| 5 | -10 |
| 6 | 4 |
| 7 | 18 |
| 8 | -19 |
| 9 | 4 |
| 10 | 27 |
| 11 | -28 |
| 12 | 4 |
| 13 | 36 |
| 14 | -37 |
| 15 | 4 |
| 16 | 45 |
| 17 | -46 |
| 18 | 4 |
| 19 | 54 |
| 20 | -55 |
| 21 | 4 |
| 22 | 63 |
| 23 | -64 |
| 24 | 4 |
| 25 | 72 |
| 26 | -73 |
| 27 | 4 |
| 28 | 81 |
| 29 | -82 |
| 30 | 4 |
| 31 | 90 |
| 32 | -91 |
| 33 | 4 |
| 34 | 99 |
| 35 | -100 |
| 36 | 4 |
| 37 | 108 |
| 38 | -109 |
| 39 | 4 |
| 40 | 117 |
| 41 | -118 |
| 42 | 4 |
| 43 | 126 |
| 44 | -127 |
| 45 | 4 |
| 46 | 135 |
| 47 | -136 |
| 48 | 4 |
| 49 | 144 |
| 50 | -145 |
| 51 | 4 |
| 52 | 153 |
| 53 | -154 |
| 54 | 4 |
| 55 | 162 |
| 56 | -163 |
| 57 | 4 |
| 58 | 171 |
| 59 | -172 |
| 60 | 4 |
| 61 | 180 |
| 62 | -181 |
| 63 | 4 |
| 64 | 189 |