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 | -1 |
| 3 | 0 |
| 4 | -1 |
| 5 | -2 |
| 6 | -7 |
| 7 | -18 |
| 8 | -50 |
| 9 | -138 |
| 10 | -386 |
| 11 | -1092 |
| 12 | -3122 |
| 13 | -9004 |
| 14 | -26173 |
| 15 | -76606 |
| 16 | -225584 |
| 17 | -667880 |
| 18 | -1986932 |
| 19 | -5936754 |
| 20 | -17807936 |
| 21 | -53606646 |
| 22 | -161892564 |
| 23 | -490363820 |
| 24 | -1489319219 |
| 25 | -4534631182 |
| 26 | -13838799043 |
| 27 | -42323692348 |
| 28 | -129697503097 |
| 29 | -398183735878 |
| 30 | -1224576726538 |
| 31 | -3772166985448 |
| 32 | -11637362223230 |
| 33 | -35953168834338 |
| 34 | -111225021683891 |