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 | 4 |
| 2 | 12 |
| 3 | 30 |
| 4 | 68 |
| 5 | 146 |
| 6 | 304 |
| 7 | 622 |
| 8 | 1260 |
| 9 | 2538 |
| 10 | 5096 |
| 11 | 10214 |
| 12 | 20452 |
| 13 | 40930 |
| 14 | 81888 |
| 15 | 163806 |
| 16 | 327644 |
| 17 | 655322 |
| 18 | 1310680 |
| 19 | 2621398 |
| 20 | 5242836 |
| 21 | 10485714 |
| 22 | 20971472 |
| 23 | 41942990 |
| 24 | 83886028 |
| 25 | 167772106 |
| 26 | 335544264 |
| 27 | 671088582 |
| 28 | 1342177220 |
| 29 | 2684354498 |