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 | 2 |
| 2 | 10 |
| 3 | 30 |
| 4 | 98 |
| 5 | 270 |
| 6 | 818 |
| 7 | 2382 |
| 8 | 7282 |
| 9 | 21818 |
| 10 | 65650 |
| 11 | 196406 |
| 12 | 589982 |
| 13 | 1768938 |
| 14 | 5309294 |
| 15 | 15924930 |
| 16 | 47779238 |
| 17 | 143322850 |
| 18 | 429998586 |
| 19 | 1289970842 |
| 20 | 3869957114 |
| 21 | 11609762666 |
| 22 | 34829416842 |
| 23 | 104488103446 |