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 | 3 |
| 3 | 6 |
| 4 | 10 |
| 5 | -39 |
| 6 | -546 |
| 7 | -3563 |
| 8 | -18918 |
| 9 | -68472 |
| 10 | -47978 |
| 11 | 2060310 |
| 12 | 25856241 |
| 13 | 210422728 |
| 14 | 1367033271 |
| 15 | 6837535155 |
| 16 | 18339297562 |
| 17 | -114989342976 |
| 18 | -2525856651999 |
| 19 | -27658429475813 |
| 20 | -235591084478085 |
| 21 | -1658029364805855 |
| 22 | -9188248947018893 |
| 23 | -28582654956147315 |
| 24 | 177119046663378954 |