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 | 0 |
| 2 | 2 |
| 3 | 9 |
| 4 | 26 |
| 5 | 63 |
| 6 | 140 |
| 7 | 297 |
| 8 | 614 |
| 9 | 1251 |
| 10 | 2528 |
| 11 | 5085 |
| 12 | 10202 |
| 13 | 20439 |
| 14 | 40916 |
| 15 | 81873 |
| 16 | 163790 |
| 17 | 327627 |
| 18 | 655304 |
| 19 | 1310661 |
| 20 | 2621378 |
| 21 | 5242815 |
| 22 | 10485692 |
| 23 | 20971449 |
| 24 | 41942966 |
| 25 | 83886003 |
| 26 | 167772080 |
| 27 | 335544237 |
| 28 | 671088554 |
| 29 | 1342177191 |