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 | 2 |
| 2 | 3 |
| 3 | 5 |
| 4 | 9 |
| 5 | 18 |
| 6 | 39 |
| 7 | 91 |
| 8 | 226 |
| 9 | 594 |
| 10 | 1643 |
| 11 | 4763 |
| 12 | 14419 |
| 13 | 45444 |
| 14 | 148714 |
| 15 | 504150 |
| 16 | 1766930 |
| 17 | 6390720 |
| 18 | 23815168 |
| 19 | 91306968 |
| 20 | 359694457 |
| 21 | 1454213026 |
| 22 | 6027213531 |
| 23 | 25583995337 |
| 24 | 111118605583 |
| 25 | 493407322280 |
| 26 | 2238131105770 |
| 27 | 10363617299670 |
| 28 | 48954143141361 |