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 | 1 |
| 4 | 0 |
| 5 | -17 |
| 6 | -32 |
| 7 | 103 |
| 8 | 976 |
| 9 | 2287 |
| 10 | -12816 |
| 11 | -143585 |
| 12 | -481016 |
| 13 | 2339335 |
| 14 | 39769720 |
| 15 | 209863327 |
| 16 | -397553376 |
| 17 | -16949434913 |
| 18 | -142681662368 |
| 19 | -233212601153 |
| 20 | 9138353475736 |
| 21 | 128343346833463 |
| 22 | 702261255539496 |
| 23 | -4251314594919617 |
| 24 | -135331386127555856 |