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 | 1 |
| 3 | 3 |
| 4 | 11 |
| 5 | 47 |
| 6 | 221 |
| 7 | 1113 |
| 8 | 5903 |
| 9 | 32607 |
| 10 | 186143 |
| 11 | 1092015 |
| 12 | 6555515 |
| 13 | 40137219 |
| 14 | 249984481 |
| 15 | 1580468321 |
| 16 | 10125395007 |
| 17 | 65639436955 |
| 18 | 430048061915 |
| 19 | 2844592155631 |
| 20 | 18979693010495 |
| 21 | 127641472658231 |
| 22 | 864645413540671 |
| 23 | 5896221199266519 |
| 24 | 40455246946190079 |