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) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 9 |
| 4 | 18 |
| 5 | 37 |
| 6 | 74 |
| 7 | 149 |
| 8 | 298 |
| 9 | 597 |
| 10 | 1194 |
| 11 | 2389 |
| 12 | 4778 |
| 13 | 9557 |
| 14 | 19114 |
| 15 | 38229 |
| 16 | 76458 |
| 17 | 152917 |
| 18 | 305834 |
| 19 | 611669 |
| 20 | 1223338 |
| 21 | 2446677 |
| 22 | 4893354 |
| 23 | 9786709 |
| 24 | 19573418 |
| 25 | 39146837 |
| 26 | 78293674 |
| 27 | 156587349 |
| 28 | 313174698 |
| 29 | 626349397 |
| 30 | 1252698794 |
| 31 | 2505397589 |