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 | 4 |
| 2 | 4 |
| 3 | 9 |
| 4 | 15 |
| 5 | 33 |
| 6 | 65 |
| 7 | 129 |
| 8 | 254 |
| 9 | 511 |
| 10 | 1027 |
| 11 | 2047 |
| 12 | 4097 |
| 13 | 8193 |
| 14 | 16382 |
| 15 | 32765 |
| 16 | 65531 |
| 17 | 131073 |
| 18 | 262142 |
| 19 | 524289 |
| 20 | 1048577 |
| 21 | 2097149 |
| 22 | 4194311 |
| 23 | 8388607 |
| 24 | 16777219 |
| 25 | 33554429 |
| 26 | 67108867 |
| 27 | 134217731 |
| 28 | 268435457 |
| 29 | 536870918 |
| 30 | 1073741821 |
| 31 | 2147483649 |
| 32 | 4294967297 |
| 33 | 8589934589 |