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 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 17 |
| 4 | 98 |
| 5 | 678 |
| 6 | 5687 |
| 7 | 55656 |
| 8 | 626161 |
| 9 | 7963511 |
| 10 | 113027113 |
| 11 | 1770785023 |
| 12 | 30346490633 |
| 13 | 564546034917 |
| 14 | 11327726548719 |
| 15 | 243811768229012 |
| 16 | 5602495216123312 |
| 17 | 136878883607160468 |
| 18 | 3542830077444873188 |
| 19 | 96835203745704714722 |
| 20 | 2787051847418347608600 |