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 | 3 |
| 1 | -7 |
| 2 | 11 |
| 3 | 233 |
| 4 | -3357 |
| 5 | 25673 |
| 6 | -102709 |
| 7 | -319207 |
| 8 | 9893763 |
| 9 | -97727527 |
| 10 | 563250251 |
| 11 | -818302327 |
| 12 | -23939051037 |
| 13 | 331342081193 |
| 14 | -2482627432309 |
| 15 | 9536407068473 |
| 16 | 35533850058243 |
| 17 | -988203251837767 |
| 18 | 9543386061052811 |
| 19 | -53687973726459607 |
| 20 | 64388654104236003 |
| 21 | 2442458092308867593 |