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 | 2 |
| 3 | 3 |
| 4 | 14 |
| 5 | 0 |
| 6 | 359 |
| 7 | -1988 |
| 8 | 28706 |
| 9 | -312210 |
| 10 | 4387572 |
| 11 | -62769366 |
| 12 | 1006242599 |
| 13 | -17203315363 |
| 14 | 318393704043 |
| 15 | -6296931104285 |
| 16 | 133039045075494 |
| 17 | -2986262905171914 |
| 18 | 71018001954178952 |
| 19 | -1783064497977512206 |
| 20 | 47133484019671647932 |
| 21 | -1308274154275749372040 |
| 22 | 38042727898691562357962 |