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 | -18 |
| 5 | 1 |
| 6 | 1 |
| 7 | -84 |
| 8 | 116 |
| 9 | -1 |
| 10 | 1 |
| 11 | -214 |
| 12 | 1707 |
| 13 | -470 |
| 14 | 1 |
| 15 | 1 |
| 16 | -408 |
| 17 | 9430 |
| 18 | -17896 |
| 19 | 1449 |
| 20 | -1 |
| 21 | 1 |
| 22 | -666 |
| 23 | 31877 |
| 24 | -196046 |
| 25 | 124782 |
| 26 | -3724 |
| 27 | 1 |
| 28 | 1 |
| 29 | -988 |
| 30 | 81720 |
| 31 | -1120768 |
| 32 | 2530948 |
| 33 | -656400 |
| 34 | 8400 |
| 35 | -1 |
| 36 | 1 |
| 37 | -1374 |
| 38 | 175727 |
| 39 | -4386774 |
| 40 | 23536143 |