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 | 12 |
| 3 | 34 |
| 4 | 96 |
| 5 | 274 |
| 6 | 792 |
| 7 | 2314 |
| 8 | 6816 |
| 9 | 20194 |
| 10 | 60072 |
| 11 | 179194 |
| 12 | 535536 |
| 13 | 1602514 |
| 14 | 4799352 |
| 15 | 14381674 |
| 16 | 43112256 |
| 17 | 129271234 |
| 18 | 387682632 |
| 19 | 1162785754 |
| 20 | 3487832976 |
| 21 | 10462450354 |
| 22 | 31385253912 |
| 23 | 94151567434 |
| 24 | 282446313696 |
| 25 | 847322163874 |
| 26 | 2541932937192 |
| 27 | 7625731702714 |