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 | 1 |
| 1 | 0 |
| 2 | 3 |
| 3 | 60 |
| 4 | 2835 |
| 5 | 219240 |
| 6 | 25519725 |
| 7 | 4169185020 |
| 8 | 910363278825 |
| 9 | 256123949281200 |
| 10 | 90240816705714675 |
| 11 | 38923077574032151500 |
| 12 | 20174526711617730727275 |
| 13 | 12373285262231460281715000 |
| 14 | 8863077725980930704895768125 |
| 15 | 7332455066541096999983523547500 |