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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 31 |
| 7 | 211 |
| 8 | 841 |
| 9 | 2521 |
| 10 | 6301 |
| 11 | 13861 |
| 12 | 30691 |
| 13 | 90091 |
| 14 | 360361 |
| 15 | 1501501 |
| 16 | 5645641 |
| 17 | 18749641 |
| 18 | 56063281 |
| 19 | 157520641 |
| 20 | 445836901 |
| 21 | 1368402421 |
| 22 | 4638690211 |
| 23 | 16511900791 |
| 24 | 58059667051 |
| 25 | 195211574251 |
| 26 | 625463703151 |
| 27 | 1942351017751 |
| 28 | 6016826006101 |
| 29 | 19113287111101 |