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 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 5 |
| 6 | 34 |
| 7 | 331 |
| 8 | 4949 |
| 9 | 123764 |
| 10 | 5713987 |
| 11 | 497201633 |
| 12 | 81514244540 |
| 13 | 25084892188043 |
| 14 | 14476409634230317 |
| 15 | 15684138157859087576 |
| 16 | 31969052260961397580693 |
| 17 | 122903899605317560183278680 |
| 18 | 893542862676093238616261481156 |
| 19 | 12317116802837365393131147013965260 |