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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 11 |
| 5 | 15 |
| 6 | 36 |
| 7 | -42 |
| 8 | 666 |
| 9 | -5499 |
| 10 | 55705 |
| 11 | -611754 |
| 12 | 7342413 |
| 13 | -95449549 |
| 14 | 1336296066 |
| 15 | -20044437930 |
| 16 | 320711010756 |
| 17 | -5452087178007 |
| 18 | 98137569210111 |
| 19 | -1864613814984794 |
| 20 | 37292276299704735 |
| 21 | -783137802293788809 |
| 22 | 17229031650463366448 |
| 23 | -396267727960657413354 |