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 | 1 |
| 3 | -1 |
| 4 | -16 |
| 5 | -111 |
| 6 | -691 |
| 7 | -4145 |
| 8 | -23080 |
| 9 | -96159 |
| 10 | 195137 |
| 11 | 13914911 |
| 12 | 284958904 |
| 13 | 4842967921 |
| 14 | 77613841629 |
| 15 | 1219132694767 |
| 16 | 19006810258064 |
| 17 | 294117291312577 |
| 18 | 4469910552829473 |
| 19 | 64942899785556031 |
| 20 | 841752172982238304 |
| 21 | 7465153745073705041 |
| 22 | -61832090598783228403 |
| 23 | -6408471053640082778097 |