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) |
|---|---|
| 2 | 1 |
| 3 | 6 |
| 4 | 23 |
| 5 | 73 |
| 6 | 211 |
| 7 | 581 |
| 8 | 1560 |
| 9 | 4135 |
| 10 | 10890 |
| 11 | 28590 |
| 12 | 74946 |
| 13 | 196326 |
| 14 | 514123 |
| 15 | 1346148 |
| 16 | 3524441 |
| 17 | 9227311 |
| 18 | 24157645 |
| 19 | 63245795 |
| 20 | 165579930 |
| 21 | 433494205 |
| 22 | 1134902916 |
| 23 | 2971214796 |
| 24 | 7778741748 |
| 25 | 20365010748 |
| 26 | 53316290821 |
| 27 | 139583862066 |