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 | 9 |
| 2 | 450 |
| 3 | 21186 |
| 4 | 995355 |
| 5 | 46760580 |
| 6 | 2196752004 |
| 7 | 103200583725 |
| 8 | 4848230683206 |
| 9 | 227763641527110 |
| 10 | 10700042921091135 |
| 11 | 502674253649756424 |
| 12 | 23614989878617461000 |
| 13 | 1109401850041370910801 |
| 14 | 52118271962065815346890 |
| 15 | 2448449380367051950393290 |