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 | -2 |
| 3 | 14 |
| 4 | -50 |
| 5 | 206 |
| 6 | -818 |
| 7 | 3278 |
| 8 | -13106 |
| 9 | 52430 |
| 10 | -209714 |
| 11 | 838862 |
| 12 | -3355442 |
| 13 | 13421774 |
| 14 | -53687090 |
| 15 | 214748366 |
| 16 | -858993458 |
| 17 | 3435973838 |
| 18 | -13743895346 |
| 19 | 54975581390 |
| 20 | -219902325554 |
| 21 | 879609302222 |
| 22 | -3518437208882 |
| 23 | 14073748835534 |
| 24 | -56294995342130 |