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) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 4 |
| 4 | 12 |
| 5 | 36 |
| 6 | 104 |
| 7 | 260 |
| 8 | 628 |
| 9 | 1448 |
| 10 | 3344 |
| 11 | 7464 |
| 12 | 16564 |
| 13 | 36180 |
| 14 | 78480 |
| 15 | 169232 |
| 16 | 362732 |
| 17 | 774172 |
| 18 | 1645508 |
| 19 | 3485788 |
| 20 | 7360208 |
| 21 | 15503432 |
| 22 | 32571360 |
| 23 | 68289536 |
| 24 | 142880552 |
| 25 | 298417848 |
| 26 | 622194236 |
| 27 | 1295266596 |
| 28 | 2692514348 |
| 29 | 5589496748 |
| 30 | 11588789220 |
| 31 | 23998902548 |