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 | 1 |
| 4 | 4 |
| 5 | 13 |
| 6 | 38 |
| 7 | 106 |
| 8 | 288 |
| 9 | 771 |
| 10 | 2046 |
| 11 | 5401 |
| 12 | 14212 |
| 13 | 37324 |
| 14 | 97904 |
| 15 | 256621 |
| 16 | 672336 |
| 17 | 1760997 |
| 18 | 4611642 |
| 19 | 12075526 |
| 20 | 31617520 |
| 21 | 82781215 |
| 22 | 216732890 |
| 23 | 567428401 |
| 24 | 1485570024 |
| 25 | 3889310328 |
| 26 | 10182407328 |
| 27 | 26657986681 |
| 28 | 69791674108 |