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 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 18 |
| 7 | 42 |
| 8 | 80 |
| 9 | 168 |
| 10 | 330 |
| 11 | 682 |
| 12 | 1340 |
| 13 | 2730 |
| 14 | 5418 |
| 15 | 10910 |
| 16 | 21760 |
| 17 | 43690 |
| 18 | 87192 |
| 19 | 174762 |
| 20 | 349180 |
| 21 | 699006 |
| 22 | 1397418 |
| 23 | 2796202 |
| 24 | 5590960 |
| 25 | 11184800 |
| 26 | 22366890 |
| 27 | 44739072 |
| 28 | 89473020 |
| 29 | 178956970 |
| 30 | 357902670 |
| 31 | 715827882 |
| 32 | 1431633920 |
| 33 | 2863310846 |