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 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 37 |
| 5 | 123 |
| 6 | 401 |
| 7 | 1293 |
| 8 | 4131 |
| 9 | 13107 |
| 10 | 41353 |
| 11 | 129873 |
| 12 | 406319 |
| 13 | 1267093 |
| 14 | 3940431 |
| 15 | 12224579 |
| 16 | 37845117 |
| 17 | 116944371 |
| 18 | 360771417 |
| 19 | 1111332129 |
| 20 | 3418840431 |
| 21 | 10504903809 |
| 22 | 32242682787 |
| 23 | 98863833159 |
| 24 | 302863592073 |
| 25 | 927025884477 |
| 26 | 2835306153351 |
| 27 | 8665554849903 |