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 | -1 |
| 3 | -1 |
| 4 | -1 |
| 5 | -2 |
| 6 | -4 |
| 7 | -8 |
| 8 | -17 |
| 9 | -37 |
| 10 | -82 |
| 11 | -185 |
| 12 | -423 |
| 13 | -978 |
| 14 | -2283 |
| 15 | -5373 |
| 16 | -12735 |
| 17 | -30372 |
| 18 | -72832 |
| 19 | -175502 |
| 20 | -424748 |
| 21 | -1032004 |
| 22 | -2516347 |
| 23 | -6155441 |
| 24 | -15101701 |
| 25 | -37150472 |
| 26 | -91618049 |
| 27 | -226460893 |
| 28 | -560954047 |
| 29 | -1392251012 |
| 30 | -3461824644 |
| 31 | -8622571758 |
| 32 | -21511212261 |