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 | -2 |
| 2 | 3 |
| 3 | -8 |
| 4 | 12 |
| 5 | -25 |
| 6 | 41 |
| 7 | -79 |
| 8 | 136 |
| 9 | -253 |
| 10 | 446 |
| 11 | -816 |
| 12 | 1455 |
| 13 | -2641 |
| 14 | 4735 |
| 15 | -8562 |
| 16 | 15391 |
| 17 | -27780 |
| 18 | 50000 |
| 19 | -90169 |
| 20 | 162389 |
| 21 | -292727 |
| 22 | 527336 |
| 23 | -950401 |
| 24 | 1712346 |
| 25 | -3085812 |
| 26 | 5560103 |
| 27 | -10019381 |
| 28 | 18053775 |
| 29 | -32532434 |
| 30 | 58620603 |