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 | 3 |
| 2 | 4 |
| 3 | 9 |
| 4 | 20 |
| 5 | 48 |
| 6 | 121 |
| 7 | 312 |
| 8 | 820 |
| 9 | 2187 |
| 10 | 5904 |
| 11 | 16104 |
| 12 | 44286 |
| 13 | 122640 |
| 14 | 341640 |
| 15 | 956593 |
| 16 | 2690420 |
| 17 | 7596480 |
| 18 | 21523360 |
| 19 | 61171656 |
| 20 | 174339220 |
| 21 | 498112057 |
| 22 | 1426411800 |
| 23 | 4093181688 |
| 24 | 11767897353 |
| 25 | 33891544377 |
| 26 | 97764070320 |
| 27 | 282429536481 |