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 | 5 |
| 4 | 13 |
| 5 | 33 |
| 6 | 85 |
| 7 | 221 |
| 8 | 581 |
| 9 | 1545 |
| 10 | 4149 |
| 11 | 11237 |
| 12 | 30657 |
| 13 | 84169 |
| 14 | 232361 |
| 15 | 644573 |
| 16 | 1795717 |
| 17 | 5021801 |
| 18 | 14091829 |
| 19 | 39665893 |
| 20 | 111965785 |
| 21 | 316857945 |
| 22 | 898797441 |
| 23 | 2555025821 |
| 24 | 7277679961 |
| 25 | 20767821489 |
| 26 | 59365259065 |
| 27 | 169967668645 |
| 28 | 487356812589 |