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) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 13 |
| 3 | 36 |
| 4 | 97 |
| 5 | 268 |
| 6 | 765 |
| 7 | 2236 |
| 8 | 6625 |
| 9 | 19764 |
| 10 | 59149 |
| 11 | 177268 |
| 12 | 531585 |
| 13 | 1594492 |
| 14 | 4783165 |
| 15 | 14349132 |
| 16 | 43046977 |
| 17 | 129140452 |
| 18 | 387420813 |
| 19 | 1162261828 |
| 20 | 3486784801 |
| 21 | 10460353644 |
| 22 | 31381060093 |
| 23 | 94143179356 |
| 24 | 282429537057 |
| 25 | 847288610068 |
| 26 | 2541865829005 |
| 27 | 7625597485716 |