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 | 1 |
| 2 | 4 |
| 3 | 6 |
| 4 | 13 |
| 5 | 39 |
| 6 | 115 |
| 7 | 295 |
| 8 | 861 |
| 9 | 2403 |
| 10 | 7048 |
| 11 | 20377 |
| 12 | 60008 |
| 13 | 175978 |
| 14 | 519589 |
| 15 | 1532455 |
| 16 | 4531277 |
| 17 | 13395656 |
| 18 | 39639758 |
| 19 | 117301153 |
| 20 | 347248981 |
| 21 | 1028011708 |
| 22 | 3043852214 |
| 23 | 9012879842 |
| 24 | 26689014028 |
| 25 | 79033362580 |
| 26 | 234045889421 |
| 27 | 693101137571 |
| 28 | 2052569508948 |