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 | 3 |
| 3 | 12 |
| 4 | 54 |
| 5 | 260 |
| 6 | 1310 |
| 7 | 6824 |
| 8 | 36478 |
| 9 | 199094 |
| 10 | 1105478 |
| 11 | 6227712 |
| 12 | 35520498 |
| 13 | 204773400 |
| 14 | 1191572004 |
| 15 | 6990859416 |
| 16 | 41313818217 |
| 17 | 245735825082 |
| 18 | 1470125583756 |
| 19 | 8840948601024 |
| 20 | 53417237877396 |
| 21 | 324123222435804 |
| 22 | 1974317194619712 |