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 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 21 |
| 6 | 60 |
| 7 | 189 |
| 8 | 595 |
| 9 | 1948 |
| 10 | 6455 |
| 11 | 21804 |
| 12 | 74464 |
| 13 | 257311 |
| 14 | 896874 |
| 15 | 3151564 |
| 16 | 11148982 |
| 17 | 39680010 |
| 18 | 141969156 |
| 19 | 510352307 |
| 20 | 1842370850 |
| 21 | 6676349598 |
| 22 | 24277171876 |
| 23 | 88556616799 |
| 24 | 323959047186 |
| 25 | 1188237214539 |
| 26 | 4368874535437 |
| 27 | 16099389598907 |
| 28 | 59449932709972 |
| 29 | 219953954227839 |