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 | 4 |
| 2 | 7 |
| 3 | 14 |
| 4 | 25 |
| 5 | 48 |
| 6 | 91 |
| 7 | 178 |
| 8 | 349 |
| 9 | 692 |
| 10 | 1375 |
| 11 | 2742 |
| 12 | 5473 |
| 13 | 10936 |
| 14 | 21859 |
| 15 | 43706 |
| 16 | 87397 |
| 17 | 174780 |
| 18 | 349543 |
| 19 | 699070 |
| 20 | 1398121 |
| 21 | 2796224 |
| 22 | 5592427 |
| 23 | 11184834 |
| 24 | 22369645 |
| 25 | 44739268 |
| 26 | 89478511 |
| 27 | 178956998 |
| 28 | 357913969 |
| 29 | 715827912 |
| 30 | 1431655795 |
| 31 | 2863311562 |