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 | 4 |
| 2 | 12 |
| 3 | 30 |
| 4 | 72 |
| 5 | 168 |
| 6 | 390 |
| 7 | 900 |
| 8 | 2076 |
| 9 | 4782 |
| 10 | 11016 |
| 11 | 25368 |
| 12 | 58422 |
| 13 | 134532 |
| 14 | 309804 |
| 15 | 713406 |
| 16 | 1642824 |
| 17 | 3783048 |
| 18 | 8711526 |
| 19 | 20060676 |
| 20 | 46195260 |
| 21 | 106377294 |
| 22 | 244963080 |
| 23 | 564094968 |
| 24 | 1298984214 |
| 25 | 2991269124 |
| 26 | 6888221772 |
| 27 | 15862029150 |
| 28 | 36526694472 |
| 29 | 84112781928 |
| 30 | 193692865350 |