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 | 2 |
| 3 | 5 |
| 4 | 7 |
| 5 | 18 |
| 6 | 43 |
| 7 | 103 |
| 8 | 264 |
| 9 | 687 |
| 10 | 1809 |
| 11 | 4836 |
| 12 | 13049 |
| 13 | 35493 |
| 14 | 97218 |
| 15 | 267857 |
| 16 | 741791 |
| 17 | 2063574 |
| 18 | 5763595 |
| 19 | 16155403 |
| 20 | 45429488 |
| 21 | 128121191 |
| 22 | 362287433 |
| 23 | 1026918632 |
| 24 | 2917313257 |
| 25 | 8304598593 |
| 26 | 23685134746 |
| 27 | 67669857661 |
| 28 | 193652803391 |