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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 273 |
| 6 | 5335 |
| 7 | 50021 |
| 8 | 291171 |
| 9 | 1263125 |
| 10 | 4434783 |
| 11 | 13355477 |
| 12 | 35672426 |
| 13 | 86686721 |
| 14 | 194886975 |
| 15 | 410820269 |
| 16 | 819819261 |
| 17 | 1561128613 |
| 18 | 2853802623 |
| 19 | 5033838173 |
| 20 | 8602315716 |
| 21 | 14291999441 |
| 22 | 23150803815 |
| 23 | 36654054741 |
| 24 | 56841404455 |
| 25 | 86496828245 |
| 26 | 129363299967 |
| 27 | 190419751685 |
| 28 | 276205278030 |