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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 5 |
| 6 | 17 |
| 7 | 41 |
| 8 | 127 |
| 9 | 365 |
| 10 | 1119 |
| 11 | 3413 |
| 12 | 10685 |
| 13 | 33561 |
| 14 | 106827 |
| 15 | 342129 |
| 16 | 1104347 |
| 17 | 3584649 |
| 18 | 11701369 |
| 19 | 38374065 |
| 20 | 126395259 |
| 21 | 417908329 |
| 22 | 1386618307 |
| 23 | 4615388353 |
| 24 | 15407188529 |
| 25 | 51569669429 |
| 26 | 173033992311 |
| 27 | 581905285089 |
| 28 | 1961034571967 |