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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 9 |
| 5 | 10 |
| 6 | 70 |
| 7 | 336 |
| 8 | 1393 |
| 9 | 6210 |
| 10 | 41331 |
| 11 | 228635 |
| 12 | 1315974 |
| 13 | 8779134 |
| 14 | 61675419 |
| 15 | 434566510 |
| 16 | 3237964993 |
| 17 | 25386526258 |
| 18 | 207569429548 |
| 19 | 1756564362651 |
| 20 | 15418550267179 |
| 21 | 140015129879331 |
| 22 | 1316198207272686 |
| 23 | 12786566843038549 |
| 24 | 128035136707876270 |
| 25 | 1319513338177755510 |