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 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 6 |
| 5 | 12 |
| 6 | 22 |
| 7 | 42 |
| 8 | 84 |
| 9 | 170 |
| 10 | 342 |
| 11 | 684 |
| 12 | 1366 |
| 13 | 2730 |
| 14 | 5460 |
| 15 | 10922 |
| 16 | 21846 |
| 17 | 43692 |
| 18 | 87382 |
| 19 | 174762 |
| 20 | 349524 |
| 21 | 699050 |
| 22 | 1398102 |
| 23 | 2796204 |
| 24 | 5592406 |
| 25 | 11184810 |
| 26 | 22369620 |
| 27 | 44739242 |
| 28 | 89478486 |
| 29 | 178956972 |
| 30 | 357913942 |
| 31 | 715827882 |
| 32 | 1431655764 |
| 33 | 2863311530 |
| 34 | 5726623062 |