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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 1 |
| 8 | 2 |
| 9 | 6 |
| 10 | 22 |
| 11 | 86 |
| 12 | 342 |
| 13 | 1366 |
| 14 | 5462 |
| 15 | 21846 |
| 16 | 86871 |
| 17 | 345952 |
| 18 | 1378208 |
| 19 | 5490992 |
| 20 | 21877296 |
| 21 | 87163696 |
| 22 | 347276080 |
| 23 | 1383600944 |
| 24 | 5512434480 |
| 25 | 21962292529 |
| 26 | 87500852554 |
| 27 | 348615720590 |
| 28 | 1388934122190 |
| 29 | 5533708922574 |
| 30 | 22047074027470 |