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 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 28 |
| 5 | 85 |
| 6 | 252 |
| 7 | 745 |
| 8 | 2202 |
| 9 | 6530 |
| 10 | 19326 |
| 11 | 57194 |
| 12 | 169341 |
| 13 | 501242 |
| 14 | 1483816 |
| 15 | 4392531 |
| 16 | 13002772 |
| 17 | 38491212 |
| 18 | 113943278 |
| 19 | 337298400 |
| 20 | 998482338 |
| 21 | 2955742400 |
| 22 | 8749688247 |
| 23 | 25901125616 |
| 24 | 76673399424 |
| 25 | 226971213462 |
| 26 | 671887935923 |
| 27 | 1988945626648 |
| 28 | 5887744768722 |
| 29 | 17429103155892 |
| 30 | 51594226501776 |