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 | 4 |
| 3 | 17 |
| 4 | 84 |
| 5 | 453 |
| 6 | 2574 |
| 7 | 15185 |
| 8 | 92119 |
| 9 | 571022 |
| 10 | 3600981 |
| 11 | 23029021 |
| 12 | 149000790 |
| 13 | 973581692 |
| 14 | 6415198045 |
| 15 | 42580369370 |
| 16 | 284427460919 |
| 17 | 1910594331920 |
| 18 | 12898153658337 |
| 19 | 87461992473577 |
| 20 | 595455441375978 |
| 21 | 4068652368270955 |
| 22 | 27891991988552554 |
| 23 | 191783482751813061 |
| 24 | 1322319472577803761 |