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 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 31 |
| 6 | 75 |
| 7 | 204 |
| 8 | 561 |
| 9 | 1499 |
| 10 | 4001 |
| 11 | 10814 |
| 12 | 29364 |
| 13 | 79704 |
| 14 | 216672 |
| 15 | 590764 |
| 16 | 1614421 |
| 17 | 4419049 |
| 18 | 12116139 |
| 19 | 33277722 |
| 20 | 91546143 |
| 21 | 252209535 |
| 22 | 695803659 |
| 23 | 1922166420 |
| 24 | 5316714156 |
| 25 | 14723570406 |
| 26 | 40820144106 |
| 27 | 113293243636 |
| 28 | 314759548879 |
| 29 | 875342190283 |
| 30 | 2436582442381 |