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 | 6 |
| 2 | 108 |
| 3 | 972 |
| 4 | 6480 |
| 5 | 36450 |
| 6 | 183708 |
| 7 | 857304 |
| 8 | 3779136 |
| 9 | 15943230 |
| 10 | 64953900 |
| 11 | 257217444 |
| 12 | 994857552 |
| 13 | 3772168218 |
| 14 | 14061928860 |
| 15 | 51656065200 |
| 16 | 187339329792 |
| 17 | 671787127926 |
| 18 | 2384960530284 |
| 19 | 8391527791740 |
| 20 | 29288988968400 |
| 21 | 101486346775506 |