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 | 5 |
| 2 | 15 |
| 3 | 45 |
| 4 | 107 |
| 5 | 265 |
| 6 | 615 |
| 7 | 1485 |
| 8 | 3227 |
| 9 | 7225 |
| 10 | 15735 |
| 11 | 35325 |
| 12 | 75019 |
| 13 | 163145 |
| 14 | 348135 |
| 15 | 761805 |
| 16 | 1589147 |
| 17 | 3374905 |
| 18 | 7077495 |
| 19 | 15138045 |
| 20 | 31390219 |
| 21 | 66122825 |
| 22 | 137816295 |
| 23 | 292344525 |
| 24 | 601532059 |
| 25 | 1253593145 |
| 26 | 2591401335 |
| 27 | 5435447805 |
| 28 | 11157226763 |