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) |
|---|---|
| 5 | 0 |
| 6 | 2 |
| 7 | 6 |
| 8 | 20 |
| 9 | 68 |
| 10 | 230 |
| 11 | 776 |
| 12 | 2604 |
| 13 | 8670 |
| 14 | 28606 |
| 15 | 93494 |
| 16 | 302748 |
| 17 | 971810 |
| 18 | 3094486 |
| 19 | 9782092 |
| 20 | 30721056 |
| 21 | 95919714 |
| 22 | 297938906 |
| 23 | 921183940 |
| 24 | 2836545972 |
| 25 | 8702745304 |
| 26 | 26614653494 |
| 27 | 81159163058 |
| 28 | 246855070144 |
| 29 | 749123740876 |
| 30 | 2268700324802 |