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 | 0 |
| 6 | 1 |
| 7 | 1 |
| 8 | 7 |
| 9 | 13 |
| 10 | 55 |
| 11 | 127 |
| 12 | 435 |
| 13 | 1110 |
| 14 | 3458 |
| 15 | 9261 |
| 16 | 27460 |
| 17 | 75305 |
| 18 | 217619 |
| 19 | 603618 |
| 20 | 1720712 |
| 21 | 4799095 |
| 22 | 13580179 |
| 23 | 37979149 |
| 24 | 107045222 |
| 25 | 299800569 |
| 26 | 843242264 |
| 27 | 2363693561 |
| 28 | 6641675073 |
| 29 | 18628827667 |
| 30 | 52325428340 |