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 | 1 |
| 2 | 4 |
| 3 | 18 |
| 4 | 68 |
| 5 | 250 |
| 6 | 922 |
| 7 | 3430 |
| 8 | 12868 |
| 9 | 48618 |
| 10 | 184754 |
| 11 | 705430 |
| 12 | 2704154 |
| 13 | 10400598 |
| 14 | 40116598 |
| 15 | 155117518 |
| 16 | 601080388 |
| 17 | 2333606218 |
| 18 | 9075135298 |
| 19 | 35345263798 |
| 20 | 137846528818 |
| 21 | 538257874438 |
| 22 | 2104098963718 |
| 23 | 8233430727598 |
| 24 | 32247603683098 |