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 | 1 |
| 3 | 13 |
| 4 | -74 |
| 5 | 253 |
| 6 | -599 |
| 7 | 718 |
| 8 | 1801 |
| 9 | -15467 |
| 10 | 61126 |
| 11 | -166427 |
| 12 | 282001 |
| 13 | 87838 |
| 14 | -2977199 |
| 15 | 14095453 |
| 16 | -43682474 |
| 17 | 91553293 |
| 18 | -64624199 |
| 19 | -500858642 |
| 20 | 3085911001 |
| 21 | -10921827227 |
| 22 | 26835937126 |
| 23 | -35883240587 |
| 24 | -62107231199 |
| 25 | 633485321278 |
| 26 | -2608461525599 |
| 27 | 7340939736493 |
| 28 | -13228544952074 |