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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 1 |
| 10 | 127 |
| 11 | 463 |
| 12 | 1255 |
| 13 | 3004 |
| 14 | 6722 |
| 15 | 140570 |
| 16 | 1039260 |
| 17 | 5371627 |
| 18 | 23202077 |
| 19 | 90048525 |
| 20 | 814737785 |
| 21 | 7967774337 |
| 22 | 62895570839 |
| 23 | 417560407223 |
| 24 | 2455461090505 |
| 25 | 18440499041402 |
| 26 | 179627278800426 |
| 27 | 1770970802250146 |