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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 26 |
| 6 | 97 |
| 7 | 333 |
| 8 | 1085 |
| 9 | 3411 |
| 10 | 10448 |
| 11 | 31376 |
| 12 | 92773 |
| 13 | 270907 |
| 14 | 783003 |
| 15 | 2243815 |
| 16 | 6383550 |
| 17 | 18048494 |
| 18 | 50755897 |
| 19 | 142067625 |
| 20 | 396014681 |
| 21 | 1099863867 |
| 22 | 3044737100 |
| 23 | 8404071596 |
| 24 | 23135752141 |
| 25 | 63538808311 |
| 26 | 174120317367 |
| 27 | 476207551183 |