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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 7 |
| 6 | 26 |
| 7 | 69 |
| 8 | 246 |
| 9 | 818 |
| 10 | 2976 |
| 11 | 10791 |
| 12 | 40591 |
| 13 | 153959 |
| 14 | 594753 |
| 15 | 2320696 |
| 16 | 9159498 |
| 17 | 36467012 |
| 18 | 146411208 |
| 19 | 592046830 |
| 20 | 2409946566 |
| 21 | 9867745442 |
| 22 | 40623068380 |
| 23 | 168058068487 |
| 24 | 698400767839 |
| 25 | 2914407151002 |
| 26 | 12208398647345 |
| 27 | 51322369218674 |
| 28 | 216463504458521 |