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 | 10 |
| 3 | 22 |
| 4 | 46 |
| 5 | 94 |
| 6 | 190 |
| 7 | 382 |
| 8 | 766 |
| 9 | 1534 |
| 10 | 3070 |
| 11 | 6142 |
| 12 | 12286 |
| 13 | 24574 |
| 14 | 49150 |
| 15 | 98302 |
| 16 | 196606 |
| 17 | 393214 |
| 18 | 786430 |
| 19 | 1572862 |
| 20 | 3145726 |
| 21 | 6291454 |
| 22 | 12582910 |
| 23 | 25165822 |
| 24 | 50331646 |
| 25 | 100663294 |
| 26 | 201326590 |
| 27 | 402653182 |
| 28 | 805306366 |
| 29 | 1610612734 |
| 30 | 3221225470 |