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 | 2 |
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 53 |
| 5 | 227 |
| 6 | 1092 |
| 7 | 5791 |
| 8 | 33350 |
| 9 | 206511 |
| 10 | 1365563 |
| 11 | 9590847 |
| 12 | 71216713 |
| 13 | 556861216 |
| 14 | 4569168866 |
| 15 | 39222394456 |
| 16 | 351304769679 |
| 17 | 3275433717440 |
| 18 | 31723522878974 |
| 19 | 318571978752719 |
| 20 | 3311400814816987 |
| 21 | 35573458376435132 |
| 22 | 394404160256111139 |
| 23 | 4507130777468928696 |