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 | -1 |
| 2 | 11 |
| 3 | -3 |
| 4 | 127 |
| 5 | -5 |
| 6 | 221 |
| 7 | -7 |
| 8 | 367 |
| 9 | -9 |
| 10 | -1895 |
| 11 | -11 |
| 12 | 1447237 |
| 13 | -13 |
| 14 | -57253 |
| 15 | -15 |
| 16 | 118526399 |
| 17 | -17 |
| 18 | -5749677193 |
| 19 | -19 |
| 20 | 91546283957 |
| 21 | -21 |
| 22 | -1792042789427 |
| 23 | -23 |
| 24 | 1982765468376757 |
| 25 | -25 |
| 26 | -286994504449237 |
| 27 | -27 |
| 28 | 3187598676787485443 |
| 29 | -29 |
| 30 | -4625594554880206360895 |
| 31 | -31 |