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) |
|---|---|
| 1 | 0 |
| 2 | -1 |
| 3 | -2 |
| 4 | -3 |
| 5 | -4 |
| 6 | -10 |
| 7 | -20 |
| 8 | -35 |
| 9 | -56 |
| 10 | -126 |
| 11 | -252 |
| 12 | -462 |
| 13 | -792 |
| 14 | -1716 |
| 15 | -3432 |
| 16 | -6435 |
| 17 | -11440 |
| 18 | -24310 |
| 19 | -48620 |
| 20 | -92378 |
| 21 | -167960 |
| 22 | -352716 |
| 23 | -705432 |
| 24 | -1352078 |
| 25 | -2496144 |
| 26 | -5200300 |
| 27 | -10400600 |
| 28 | -20058300 |
| 29 | -37442160 |
| 30 | -77558760 |
| 31 | -155117520 |
| 32 | -300540195 |