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 | 2 |
| 2 | 9 |
| 3 | 58 |
| 4 | 506 |
| 5 | 5462 |
| 6 | 70226 |
| 7 | 1038578 |
| 8 | 17274974 |
| 9 | 317292692 |
| 10 | 6346909285 |
| 11 | 136723993122 |
| 12 | 3143278648954 |
| 13 | 76547029418394 |
| 14 | 1962350550273130 |
| 15 | 52679691605422354 |
| 16 | 1474290522744355250 |
| 17 | 42847373913958703100 |
| 18 | 1288899422418558314550 |
| 19 | 40013380588722843337620 |