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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 12 |
| 5 | 27 |
| 6 | 63 |
| 7 | 141 |
| 8 | 297 |
| 9 | 594 |
| 10 | 1146 |
| 11 | 2169 |
| 12 | 4095 |
| 13 | 7827 |
| 14 | 15291 |
| 15 | 30582 |
| 16 | 62256 |
| 17 | 127791 |
| 18 | 262143 |
| 19 | 534129 |
| 20 | 1078101 |
| 21 | 2156202 |
| 22 | 4282878 |
| 23 | 8477181 |
| 24 | 16777215 |
| 25 | 33288711 |
| 26 | 66311703 |
| 27 | 132623406 |
| 28 | 266043972 |
| 29 | 534479427 |
| 30 | 1073741823 |
| 31 | 2154658101 |