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 | 9 |
| 3 | 27 |
| 4 | 78 |
| 5 | 222 |
| 6 | 624 |
| 7 | 1740 |
| 8 | 4824 |
| 9 | 13320 |
| 10 | 36672 |
| 11 | 100752 |
| 12 | 276384 |
| 13 | 757344 |
| 14 | 2073600 |
| 15 | 5674176 |
| 16 | 15520128 |
| 17 | 42437760 |
| 18 | 116014080 |
| 19 | 317100288 |
| 20 | 866621952 |
| 21 | 2368230912 |
| 22 | 6471278592 |
| 23 | 17682164736 |
| 24 | 48313178112 |
| 25 | 132003268608 |
| 26 | 360658059264 |