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 | 2 |
| 2 | 6 |
| 3 | 16 |
| 4 | 42 |
| 5 | 106 |
| 6 | 267 |
| 7 | 656 |
| 8 | 1602 |
| 9 | 3868 |
| 10 | 9270 |
| 11 | 22048 |
| 12 | 52140 |
| 13 | 122580 |
| 14 | 286798 |
| 15 | 667944 |
| 16 | 1549259 |
| 17 | 3579738 |
| 18 | 8242638 |
| 19 | 18917600 |
| 20 | 43286909 |
| 21 | 98768820 |
| 22 | 224768425 |
| 23 | 510235760 |
| 24 | 1155553468 |
| 25 | 2611251662 |
| 26 | 5888421059 |
| 27 | 13252176464 |
| 28 | 29768501556 |
| 29 | 66749440076 |
| 30 | 149415504274 |