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 | 0 |
| 2 | 0 |
| 3 | -3 |
| 4 | -3 |
| 5 | -3 |
| 6 | 30 |
| 7 | 72 |
| 8 | 123 |
| 9 | -313 |
| 10 | -1533 |
| 11 | -3888 |
| 12 | 827 |
| 13 | 28893 |
| 14 | 107637 |
| 15 | 116372 |
| 16 | -420813 |
| 17 | -2657823 |
| 18 | -5660571 |
| 19 | 1544334 |
| 20 | 57009453 |
| 21 | 190508467 |
| 22 | 207797979 |
| 23 | -955665852 |
| 24 | -5323553041 |
| 25 | -11293308333 |
| 26 | 6516682923 |
| 27 | 125714105729 |
| 28 | 411566197974 |
| 29 | 382778797437 |
| 30 | -2328595584491 |