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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 7 |
| 6 | 39 |
| 7 | 332 |
| 8 | 4735 |
| 9 | 113176 |
| 10 | 4629463 |
| 11 | 327695586 |
| 12 | 40525166511 |
| 13 | 8850388574939 |
| 14 | 3453378695335727 |
| 15 | 2435485662537561705 |
| 16 | 3137225298932374490227 |
| 17 | 7448146273273417700880931 |
| 18 | 32837456713651735794742705141 |
| 19 | 270528237651574516777595556494978 |
| 20 | 4186091025846007046878947026003803389 |