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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 40 |
| 5 | 145 |
| 6 | 526 |
| 7 | 1908 |
| 8 | 6921 |
| 9 | 25105 |
| 10 | 91065 |
| 11 | 330326 |
| 12 | 1198213 |
| 13 | 4346356 |
| 14 | 15765820 |
| 15 | 57188385 |
| 16 | 207443151 |
| 17 | 752472043 |
| 18 | 2729490816 |
| 19 | 9900859685 |
| 20 | 35914032730 |
| 21 | 130273308376 |
| 22 | 472548850273 |
| 23 | 1714107200301 |
| 24 | 6217692609825 |
| 25 | 22553841080350 |
| 26 | 81811015661001 |