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 | 9 |
| 3 | 162 |
| 4 | 2025 |
| 5 | 21870 |
| 6 | 219429 |
| 7 | 2112642 |
| 8 | 19847025 |
| 9 | 183642390 |
| 10 | 1682955549 |
| 11 | 15327821322 |
| 12 | 139038251625 |
| 13 | 1257873017310 |
| 14 | 11360034454869 |
| 15 | 102475388237202 |
| 16 | 923689006041825 |
| 17 | 8321664254958630 |
| 18 | 74945757885541389 |
| 19 | 674816499677616282 |