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 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 22 |
| 6 | 61 |
| 7 | 142 |
| 8 | 420 |
| 9 | 1017 |
| 10 | 3146 |
| 11 | 7844 |
| 12 | 25083 |
| 13 | 63974 |
| 14 | 209875 |
| 15 | 545060 |
| 16 | 1824949 |
| 17 | 4810138 |
| 18 | 16374993 |
| 19 | 43695535 |
| 20 | 150820899 |
| 21 | 406669871 |
| 22 | 1420155120 |
| 23 | 3863613980 |
| 24 | 13627843933 |
| 25 | 37363313071 |
| 26 | 132933980698 |
| 27 | 366939582498 |
| 28 | 1315436809855 |
| 29 | 3652777067949 |
| 30 | 13182411646150 |