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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | -1 |
| 5 | -7 |
| 6 | -6 |
| 7 | -1 |
| 8 | 43 |
| 9 | 47 |
| 10 | 52 |
| 11 | -383 |
| 12 | -465 |
| 13 | -1007 |
| 14 | 4514 |
| 15 | 5503 |
| 16 | 19619 |
| 17 | -66721 |
| 18 | -73932 |
| 19 | -419863 |
| 20 | 1193767 |
| 21 | 1058777 |
| 22 | 10010890 |
| 23 | -25204097 |
| 24 | -14340981 |
| 25 | -265465457 |
| 26 | 615761444 |
| 27 | 107400049 |
| 28 | 7783328783 |
| 29 | -17133920383 |
| 30 | 4668727362 |