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 | 2 |
| 2 | 3 |
| 3 | 4 |
| 4 | 6 |
| 5 | 7 |
| 6 | 8 |
| 7 | 11 |
| 8 | 12 |
| 9 | 18 |
| 10 | 21 |
| 11 | 26 |
| 12 | 68 |
| 13 | 656 |
| 14 | 2336 |
| 15 | 8768 |
| 16 | 133376 |
| 17 | 528896 |
| 18 | 34360918016 |
| 19 | 35184409837568 |
| 20 | 576460757135261696 |