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 | -2 |
| 3 | -3 |
| 4 | -4 |
| 5 | 30 |
| 6 | 274 |
| 7 | 1841 |
| 8 | 9358 |
| 9 | 32463 |
| 10 | -41557 |
| 11 | -2265846 |
| 12 | -28939286 |
| 13 | -272101778 |
| 14 | -2038274408 |
| 15 | -10494221259 |
| 16 | 9056975574 |
| 17 | 1244820826687 |
| 18 | 22703501504125 |
| 19 | 299864024917632 |
| 20 | 3221417281127823 |
| 21 | 26849622543478562 |
| 22 | 110101743392268978 |
| 23 | -1810492304600468063 |