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 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 1 |
| 8 | 2 |
| 9 | 4 |
| 10 | 7 |
| 11 | 14 |
| 12 | 28 |
| 13 | 56 |
| 14 | 112 |
| 15 | 223 |
| 16 | 444 |
| 17 | 884 |
| 18 | 1761 |
| 19 | 3508 |
| 20 | 6988 |
| 21 | 13920 |
| 22 | 27728 |
| 23 | 55233 |
| 24 | 110022 |
| 25 | 219160 |
| 26 | 436559 |
| 27 | 869610 |
| 28 | 1732232 |
| 29 | 3450544 |
| 30 | 6873360 |
| 31 | 13691487 |
| 32 | 27272952 |
| 33 | 54326744 |
| 34 | 108216929 |
| 35 | 215564248 |
| 36 | 429396264 |
| 37 | 855341984 |
| 38 | 1703810608 |
| 39 | 3393929729 |