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 | 3 |
| 1 | 20 |
| 2 | 154 |
| 3 | 1268 |
| 4 | 10738 |
| 5 | 92060 |
| 6 | 794314 |
| 7 | 6882308 |
| 8 | 59830498 |
| 9 | 521657900 |
| 10 | 4560585274 |
| 11 | 39971171348 |
| 12 | 351149544658 |
| 13 | 3091623236540 |
| 14 | 27274843749034 |
| 15 | 241075518532388 |
| 16 | 2134495208609218 |
| 17 | 18928981642491980 |
| 18 | 168109034193901594 |
| 19 | 1494966906911109428 |
| 20 | 13310586967150560178 |