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 | 4 |
| 1 | 7 |
| 2 | 15 |
| 3 | 37 |
| 4 | 99 |
| 5 | 277 |
| 6 | 795 |
| 7 | 2317 |
| 8 | 6819 |
| 9 | 20197 |
| 10 | 60075 |
| 11 | 179197 |
| 12 | 535539 |
| 13 | 1602517 |
| 14 | 4799355 |
| 15 | 14381677 |
| 16 | 43112259 |
| 17 | 129271237 |
| 18 | 387682635 |
| 19 | 1162785757 |
| 20 | 3487832979 |
| 21 | 10462450357 |
| 22 | 31385253915 |
| 23 | 94151567437 |
| 24 | 282446313699 |
| 25 | 847322163877 |
| 26 | 2541932937195 |
| 27 | 7625731702717 |