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) |
|---|---|
| 4 | 1 |
| 5 | 1 |
| 6 | 5 |
| 7 | 17 |
| 8 | 57 |
| 9 | 193 |
| 10 | 649 |
| 11 | 2161 |
| 12 | 7113 |
| 13 | 23137 |
| 14 | 74417 |
| 15 | 236913 |
| 16 | 747401 |
| 17 | 2339137 |
| 18 | 7270189 |
| 19 | 22460801 |
| 20 | 69031105 |
| 21 | 211206529 |
| 22 | 643684485 |
| 23 | 1955082321 |
| 24 | 5920720729 |
| 25 | 17884040961 |
| 26 | 53898818389 |
| 27 | 162120056257 |
| 28 | 486791503521 |
| 29 | 1459448379329 |