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 | 2 |
| 2 | 3 |
| 3 | 7 |
| 4 | 8 |
| 5 | 15 |
| 6 | 32 |
| 7 | 64 |
| 8 | 63 |
| 9 | 224 |
| 10 | 255 |
| 11 | 1280 |
| 12 | 512 |
| 13 | 3968 |
| 14 | 6399 |
| 15 | 10240 |
| 16 | 4095 |
| 17 | 14336 |
| 18 | 32768 |
| 19 | 65535 |
| 20 | 229375 |
| 21 | 180224 |
| 22 | 483327 |
| 23 | 262143 |
| 24 | 2097151 |
| 25 | 1048575 |
| 26 | 14680064 |
| 27 | 17432576 |
| 28 | 33554432 |
| 29 | 67108864 |
| 30 | 16777215 |