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) |
|---|---|
| 2 | 23 |
| 3 | 50 |
| 4 | 160 |
| 5 | 466 |
| 6 | 1432 |
| 7 | 4362 |
| 8 | 12960 |
| 9 | 39138 |
| 10 | 117416 |
| 11 | 353274 |
| 12 | 1059824 |
| 13 | 3183570 |
| 14 | 9550712 |
| 15 | 28668522 |
| 16 | 86038336 |
| 17 | 258246082 |
| 18 | 774607176 |
| 19 | 2324083674 |
| 20 | 6973299600 |
| 21 | 20918850226 |
| 22 | 62758647832 |
| 23 | 188280137802 |
| 24 | 564857190624 |
| 25 | 1694571571874 |
| 26 | 5083681161192 |
| 27 | 15251177701306 |