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 | 4 |
| 3 | 135 |
| 4 | 1368 |
| 5 | 7350 |
| 6 | 28400 |
| 7 | 89073 |
| 8 | 241220 |
| 9 | 585057 |
| 10 | 1301420 |
| 11 | 2699125 |
| 12 | 5282172 |
| 13 | 9842430 |
| 14 | 17584416 |
| 15 | 30289835 |
| 16 | 50530680 |
| 17 | 81940901 |
| 18 | 129557940 |
| 19 | 200246795 |
| 20 | 303220720 |
| 21 | 450674190 |
| 22 | 658545360 |
| 23 | 947426925 |
| 24 | 1343646044 |
| 25 | 1880535825 |
| 26 | 2599922780 |
| 27 | 3553856649 |
| 28 | 4806611060 |