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 | 12 |
| 4 | 52 |
| 5 | 229 |
| 6 | 1006 |
| 7 | 4387 |
| 8 | 18978 |
| 9 | 81489 |
| 10 | 347614 |
| 11 | 1474436 |
| 12 | 6223328 |
| 13 | 26156242 |
| 14 | 109528108 |
| 15 | 457167817 |
| 16 | 1902808318 |
| 17 | 7899987577 |
| 18 | 32725812958 |
| 19 | 135297527872 |
| 20 | 558357811048 |
| 21 | 2300564293942 |
| 22 | 9465003608548 |
| 23 | 38889193275142 |
| 24 | 159591154157092 |
| 25 | 654190748282074 |