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 | 3 |
| 3 | 12 |
| 4 | 42 |
| 5 | 156 |
| 6 | 554 |
| 7 | 2028 |
| 8 | 7350 |
| 9 | 26936 |
| 10 | 98874 |
| 11 | 365196 |
| 12 | 1353520 |
| 13 | 5039580 |
| 14 | 18831306 |
| 15 | 70626140 |
| 16 | 265741350 |
| 17 | 1002984060 |
| 18 | 3796211692 |
| 19 | 14406086604 |
| 20 | 54801192684 |
| 21 | 208932673508 |
| 22 | 798218225802 |
| 23 | 3055417434732 |
| 24 | 11716355452900 |