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 | 0 |
| 2 | 2 |
| 3 | 3 |
| 4 | 9 |
| 5 | 20 |
| 6 | 50 |
| 7 | 119 |
| 8 | 289 |
| 9 | 696 |
| 10 | 1682 |
| 11 | 4059 |
| 12 | 9801 |
| 13 | 23660 |
| 14 | 57122 |
| 15 | 137903 |
| 16 | 332929 |
| 17 | 803760 |
| 18 | 1940450 |
| 19 | 4684659 |
| 20 | 11309769 |
| 21 | 27304196 |
| 22 | 65918162 |
| 23 | 159140519 |
| 24 | 384199201 |
| 25 | 927538920 |
| 26 | 2239277042 |
| 27 | 5406093003 |
| 28 | 13051463049 |
| 29 | 31509019100 |
| 30 | 76069501250 |