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 | 2 |
| 2 | 7 |
| 3 | 42 |
| 4 | 376 |
| 5 | 4458 |
| 6 | 65397 |
| 7 | 1140417 |
| 8 | 23021210 |
| 9 | 527739626 |
| 10 | 13539127840 |
| 11 | 384262459699 |
| 12 | 11952683436071 |
| 13 | 404329660018435 |
| 14 | 14777538816404041 |
| 15 | 580286020131192211 |
| 16 | 24364714949633126567 |
| 17 | 1089258665667224399708 |
| 18 | 51658296648076559411788 |
| 19 | 2590348228951371235924053 |