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 | 1 |
| 2 | 5 |
| 3 | 21 |
| 4 | 86 |
| 5 | 351 |
| 6 | 1432 |
| 7 | 5842 |
| 8 | 23833 |
| 9 | 97229 |
| 10 | 396655 |
| 11 | 1618192 |
| 12 | 6601569 |
| 13 | 26931732 |
| 14 | 109870576 |
| 15 | 448227521 |
| 16 | 1828587033 |
| 17 | 7459895657 |
| 18 | 30433357674 |
| 19 | 124155792775 |
| 20 | 506505428836 |
| 21 | 2066337330754 |
| 22 | 8429820731201 |
| 23 | 34390259761825 |
| 24 | 140298353215075 |
| 25 | 572360547759276 |
| 26 | 2334999585697905 |