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 | 0 |
| 4 | 1 |
| 5 | 4 |
| 6 | 12 |
| 7 | 32 |
| 8 | 78 |
| 9 | 180 |
| 10 | 400 |
| 11 | 864 |
| 12 | 1827 |
| 13 | 3800 |
| 14 | 7800 |
| 15 | 15840 |
| 16 | 31884 |
| 17 | 63704 |
| 18 | 126480 |
| 19 | 249760 |
| 20 | 490885 |
| 21 | 960828 |
| 22 | 1873828 |
| 23 | 3642560 |
| 24 | 7060314 |
| 25 | 13649196 |
| 26 | 26324704 |
| 27 | 50662464 |
| 28 | 97309767 |
| 29 | 186571248 |
| 30 | 357119472 |
| 31 | 682524224 |
| 32 | 1302589016 |
| 33 | 2482706544 |