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 | 14 |
| 3 | 28 |
| 4 | 254 |
| 5 | 508 |
| 6 | 3556 |
| 7 | 7112 |
| 8 | 65534 |
| 9 | 131068 |
| 10 | 917476 |
| 11 | 1834952 |
| 12 | 16645636 |
| 13 | 33291272 |
| 14 | 233038904 |
| 15 | 466077808 |
| 16 | 4294967294 |
| 17 | 8589934588 |
| 18 | 60129542116 |
| 19 | 120259084232 |
| 20 | 1090921692676 |
| 21 | 2181843385352 |
| 22 | 15272903697464 |
| 23 | 30545807394928 |