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 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 24 |
| 6 | 64 |
| 7 | 166 |
| 8 | 456 |
| 9 | 1234 |
| 10 | 3454 |
| 11 | 9600 |
| 12 | 27246 |
| 13 | 77132 |
| 14 | 221336 |
| 15 | 635078 |
| 16 | 1839000 |
| 17 | 5331274 |
| 18 | 15555586 |
| 19 | 45465412 |
| 20 | 133517130 |
| 21 | 392841336 |
| 22 | 1160033656 |
| 23 | 3432015726 |
| 24 | 10182891552 |
| 25 | 30267591290 |
| 26 | 90177226062 |
| 27 | 269117947728 |
| 28 | 804699330974 |
| 29 | 2409839825756 |
| 30 | 7228746487536 |