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 | 0 |
| 3 | 2 |
| 4 | 30 |
| 5 | 202 |
| 6 | 2016 |
| 7 | 14394 |
| 8 | 151290 |
| 9 | 1294478 |
| 10 | 15660744 |
| 11 | 162298842 |
| 12 | 2274318228 |
| 13 | 27968231436 |
| 14 | 447527038848 |
| 15 | 6382757516250 |
| 16 | 114890215021650 |
| 17 | 1865385066804550 |
| 18 | 37307710791708600 |
| 19 | 679562209260462054 |