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 | 9 |
| 5 | 26 |
| 6 | 73 |
| 7 | 204 |
| 8 | 568 |
| 9 | 1581 |
| 10 | 4399 |
| 11 | 12239 |
| 12 | 34051 |
| 13 | 94736 |
| 14 | 263571 |
| 15 | 733297 |
| 16 | 2040150 |
| 17 | 5676024 |
| 18 | 15791606 |
| 19 | 43934770 |
| 20 | 122233545 |
| 21 | 340073237 |
| 22 | 946138039 |
| 23 | 2632307076 |
| 24 | 7323498533 |
| 25 | 20375142114 |
| 26 | 56686898249 |
| 27 | 157712000980 |