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) |
|---|---|
| 3 | 0 |
| 4 | 2 |
| 5 | 6 |
| 6 | 17 |
| 7 | 49 |
| 8 | 135 |
| 9 | 361 |
| 10 | 951 |
| 11 | 2493 |
| 12 | 6497 |
| 13 | 16837 |
| 14 | 43498 |
| 15 | 112164 |
| 16 | 288741 |
| 17 | 742294 |
| 18 | 1906552 |
| 19 | 4893835 |
| 20 | 12555662 |
| 21 | 32201344 |
| 22 | 82566738 |
| 23 | 211675672 |
| 24 | 542621858 |
| 25 | 1390929877 |
| 26 | 3565435302 |
| 27 | 9139718572 |
| 28 | 23430209922 |
| 29 | 60069035611 |
| 30 | 154014868677 |