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 | 2 |
| 4 | 7 |
| 5 | 13 |
| 6 | 47 |
| 7 | 111 |
| 8 | 367 |
| 9 | 1057 |
| 10 | 3474 |
| 11 | 11116 |
| 12 | 38106 |
| 13 | 131235 |
| 14 | 470882 |
| 15 | 1720959 |
| 16 | 6472129 |
| 17 | 24860957 |
| 18 | 97779665 |
| 19 | 392642763 |
| 20 | 1610045000 |
| 21 | 6732768139 |
| 22 | 28699327441 |
| 23 | 124600601174 |
| 24 | 550684155992 |
| 25 | 2476019025827 |
| 26 | 11320106871951 |
| 27 | 52598300581495 |
| 28 | 248265707440448 |
| 29 | 1189855827112636 |
| 30 | 5787965846277749 |