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 | 4 |
| 3 | 14 |
| 4 | 28 |
| 5 | 94 |
| 6 | 218 |
| 7 | 588 |
| 8 | 1366 |
| 9 | 3618 |
| 10 | 8134 |
| 11 | 20320 |
| 12 | 45592 |
| 13 | 105810 |
| 14 | 236960 |
| 15 | 539392 |
| 16 | 1174530 |
| 17 | 2612436 |
| 18 | 5628606 |
| 19 | 12226350 |
| 20 | 26130568 |
| 21 | 55938126 |
| 22 | 117997774 |
| 23 | 249680514 |
| 24 | 523032956 |
| 25 | 1094500962 |
| 26 | 2275886514 |
| 27 | 4727461792 |
| 28 | 9762182762 |
| 29 | 20148991512 |
| 30 | 41403646304 |
| 31 | 84961079990 |