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 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 29 |
| 6 | 87 |
| 7 | 273 |
| 8 | 819 |
| 9 | 2493 |
| 10 | 7497 |
| 11 | 22607 |
| 12 | 67821 |
| 13 | 203919 |
| 14 | 611757 |
| 15 | 1836363 |
| 16 | 5509437 |
| 17 | 16531749 |
| 18 | 49595247 |
| 19 | 148796757 |
| 20 | 446390271 |
| 21 | 1339201845 |
| 22 | 4017608811 |
| 23 | 12052916861 |
| 24 | 36158750583 |
| 25 | 108476535993 |
| 26 | 325429609661 |
| 27 | 976289644659 |
| 28 | 2928868963893 |
| 29 | 8786609348535 |