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 | 1 |
| 3 | 0 |
| 4 | -4 |
| 5 | -12 |
| 6 | -3 |
| 7 | 150 |
| 8 | 744 |
| 9 | 525 |
| 10 | -16799 |
| 11 | -118280 |
| 12 | -148289 |
| 13 | 4036802 |
| 14 | 37244157 |
| 15 | 68676153 |
| 16 | -1758280309 |
| 17 | -20207442595 |
| 18 | -49855713746 |
| 19 | 1245931950070 |
| 20 | 17250366460410 |
| 21 | 53991885230741 |
| 22 | -1330935478357842 |
| 23 | -21705274324058996 |
| 24 | -83339285813776419 |
| 25 | 2026672671500822591 |
| 26 | 38327819123289163864 |