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 | 2 |
| 2 | -4 |
| 3 | 6 |
| 4 | -12 |
| 5 | 16 |
| 6 | -24 |
| 7 | 38 |
| 8 | -52 |
| 9 | 74 |
| 10 | -104 |
| 11 | 142 |
| 12 | -192 |
| 13 | 258 |
| 14 | -340 |
| 15 | 446 |
| 16 | -584 |
| 17 | 756 |
| 18 | -972 |
| 19 | 1244 |
| 20 | -1580 |
| 21 | 1996 |
| 22 | -2516 |
| 23 | 3148 |
| 24 | -3924 |
| 25 | 4878 |
| 26 | -6032 |
| 27 | 7434 |
| 28 | -9136 |
| 29 | 11182 |
| 30 | -13644 |
| 31 | 16608 |
| 32 | -20148 |
| 33 | 24378 |
| 34 | -29428 |
| 35 | 35422 |
| 36 | -42540 |
| 37 | 50978 |
| 38 | -60940 |
| 39 | 72700 |
| 40 | -86556 |
| 41 | 102838 |
| 42 | -121952 |
| 43 | 144360 |
| 44 | -170564 |
| 45 | 201176 |
| 46 | -236900 |
| 47 | 278494 |
| 48 | -326876 |
| 49 | 383094 |
| 50 | -448288 |
| 51 | 523824 |
| 52 | -611248 |
| 53 | 712256 |
| 54 | -828860 |
| 55 | 963324 |
| 56 | -1118160 |
| 57 | 1296296 |
| 58 | -1501028 |
| 59 | 1736030 |
| 60 | -2005540 |