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 | 14 |
| 3 | 47 |
| 4 | 152 |
| 5 | 480 |
| 6 | 1488 |
| 7 | 4548 |
| 8 | 13744 |
| 9 | 41152 |
| 10 | 122272 |
| 11 | 360944 |
| 12 | 1059584 |
| 13 | 3095552 |
| 14 | 9005568 |
| 15 | 26101824 |
| 16 | 75404544 |
| 17 | 217191424 |
| 18 | 623928832 |
| 19 | 1788071680 |
| 20 | 5113137152 |
| 21 | 14592352256 |
| 22 | 41569120256 |
| 23 | 118219097088 |
| 24 | 335685021696 |
| 25 | 951817715712 |
| 26 | 2695241605120 |
| 27 | 7622609858560 |