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 | 1 |
| 2 | 12 |
| 3 | 651 |
| 4 | 5720 |
| 5 | 12480 |
| 6 | 17549 |
| 7 | 236588 |
| 8 | 12758199 |
| 9 | 112130200 |
| 10 | 244626200 |
| 11 | 343998201 |
| 12 | 4637596612 |
| 13 | 250086218851 |
| 14 | 2197976167920 |
| 15 | 4795162766680 |
| 16 | 6743052715749 |
| 17 | 90906168553188 |
| 18 | 4902190049156399 |
| 19 | 43084728731444400 |
| 20 | 93994780307828400 |