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 | -10 |
| 4 | 31 |
| 5 | -96 |
| 6 | 294 |
| 7 | -876 |
| 8 | 2511 |
| 9 | -6796 |
| 10 | 16698 |
| 11 | -33540 |
| 12 | 31174 |
| 13 | 184534 |
| 14 | -1627812 |
| 15 | 8912760 |
| 16 | -41466433 |
| 17 | 176963760 |
| 18 | -714194382 |
| 19 | 2766892840 |
| 20 | -10374065814 |
| 21 | 37815483948 |
| 22 | -134334781732 |
| 23 | 465432203640 |
| 24 | -1571910265770 |
| 25 | 5164302815179 |
| 26 | -16438631981418 |