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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 11 |
| 7 | 60 |
| 8 | 270 |
| 9 | 1084 |
| 10 | 4028 |
| 11 | 14144 |
| 12 | 47577 |
| 13 | 154740 |
| 14 | 489728 |
| 15 | 1514786 |
| 16 | 4593118 |
| 17 | 13682374 |
| 18 | 40106060 |
| 19 | 115824376 |
| 20 | 329901232 |
| 21 | 927585696 |
| 22 | 2576685888 |
| 23 | 7076644480 |
| 24 | 19228648192 |
| 25 | 51725149184 |