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 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 18 |
| 5 | 38 |
| 6 | 78 |
| 7 | 158 |
| 8 | 318 |
| 9 | 638 |
| 10 | 1278 |
| 11 | 2558 |
| 12 | 5118 |
| 13 | 10238 |
| 14 | 20478 |
| 15 | 40958 |
| 16 | 81918 |
| 17 | 163838 |
| 18 | 327678 |
| 19 | 655358 |
| 20 | 1310718 |
| 21 | 2621438 |
| 22 | 5242878 |
| 23 | 10485758 |
| 24 | 20971518 |
| 25 | 41943038 |
| 26 | 83886078 |
| 27 | 167772158 |
| 28 | 335544318 |
| 29 | 671088638 |
| 30 | 1342177278 |
| 31 | 2684354558 |