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 | 3 |
| 4 | 3 |
| 5 | 3 |
| 6 | 36 |
| 7 | 78 |
| 8 | 129 |
| 9 | 685 |
| 10 | 2043 |
| 11 | 4554 |
| 12 | 17233 |
| 13 | 57279 |
| 14 | 153045 |
| 15 | 509848 |
| 16 | 1724739 |
| 17 | 5117643 |
| 18 | 16445555 |
| 19 | 55165536 |
| 20 | 173225715 |
| 21 | 555899673 |
| 22 | 1847495415 |
| 23 | 5971507824 |
| 24 | 19333284247 |
| 25 | 63975307425 |
| 26 | 209807070669 |
| 27 | 685973054145 |
| 28 | 2269660792842 |
| 29 | 7501194321663 |
| 30 | 24725092907853 |