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 | 3 |
| 2 | 7 |
| 3 | 16 |
| 4 | 39 |
| 5 | 104 |
| 6 | 301 |
| 7 | 927 |
| 8 | 2983 |
| 9 | 9901 |
| 10 | 33615 |
| 11 | 116115 |
| 12 | 406627 |
| 13 | 1440039 |
| 14 | 5147891 |
| 15 | 18550588 |
| 16 | 67310955 |
| 17 | 245716112 |
| 18 | 901759969 |
| 19 | 3325067016 |
| 20 | 12312494483 |
| 21 | 45766188970 |
| 22 | 170702447097 |
| 23 | 638698318874 |
| 24 | 2396598337975 |
| 25 | 9016444758528 |
| 26 | 34003644251233 |
| 27 | 128524394659942 |
| 28 | 486793096819011 |