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 | -3 |
| 3 | -6 |
| 4 | -10 |
| 5 | -11 |
| 6 | 3 |
| 7 | 63 |
| 8 | 240 |
| 9 | 677 |
| 10 | 1622 |
| 11 | 3415 |
| 12 | 6277 |
| 13 | 9485 |
| 14 | 8917 |
| 15 | -9299 |
| 16 | -83683 |
| 17 | -309568 |
| 18 | -902995 |
| 19 | -2315518 |
| 20 | -5411355 |
| 21 | -11662530 |
| 22 | -23117627 |
| 23 | -41317787 |
| 24 | -62820880 |
| 25 | -65358588 |
| 26 | 29550902 |
| 27 | 449154266 |
| 28 | 1783671567 |
| 29 | 5453429052 |
| 30 | 14668699694 |
| 31 | 36273441659 |