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 | 2 |
| 3 | -4 |
| 4 | 1 |
| 5 | -4 |
| 6 | 4 |
| 7 | 2 |
| 8 | -11 |
| 9 | 19 |
| 10 | -4 |
| 11 | 12 |
| 12 | -82 |
| 13 | 142 |
| 14 | -84 |
| 15 | 4 |
| 16 | 288 |
| 17 | -2208 |
| 18 | 4142 |
| 19 | -2262 |
| 20 | 422 |
| 21 | -4 |
| 22 | 34560 |
| 23 | -277056 |
| 24 | 566448 |
| 25 | -327528 |
| 26 | 49938 |
| 27 | -2504 |
| 28 | 4 |
| 29 | 24883200 |
| 30 | -202141440 |
| 31 | 427397472 |
| 32 | -267303264 |
| 33 | 44330580 |
| 34 | -1580666 |
| 35 | 17368 |
| 36 | -4 |
| 37 | 125411328000 |
| 38 | -1021977907200 |
| 39 | 2179398320640 |
| 40 | -1397599077312 |