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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 4 |
| 7 | 7 |
| 8 | 16 |
| 9 | 42 |
| 10 | 111 |
| 11 | 331 |
| 12 | 1094 |
| 13 | 3829 |
| 14 | 14380 |
| 15 | 57069 |
| 16 | 237188 |
| 17 | 1027929 |
| 18 | 4622588 |
| 19 | 21494274 |
| 20 | 103077677 |
| 21 | 508743475 |
| 22 | 2579847563 |
| 23 | 13422868110 |
| 24 | 71570635306 |
| 25 | 390670937143 |