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 | 4 |
| 1 | 12 |
| 2 | 28 |
| 3 | 56 |
| 4 | 112 |
| 5 | 228 |
| 6 | 460 |
| 7 | 920 |
| 8 | 1840 |
| 9 | 3684 |
| 10 | 7372 |
| 11 | 14744 |
| 12 | 29488 |
| 13 | 58980 |
| 14 | 117964 |
| 15 | 235928 |
| 16 | 471856 |
| 17 | 943716 |
| 18 | 1887436 |
| 19 | 3774872 |
| 20 | 7549744 |
| 21 | 15099492 |
| 22 | 30198988 |
| 23 | 60397976 |
| 24 | 120795952 |
| 25 | 241591908 |
| 26 | 483183820 |
| 27 | 966367640 |
| 28 | 1932735280 |
| 29 | 3865470564 |
| 30 | 7730941132 |
| 31 | 15461882264 |