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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 21 |
| 7 | 53 |
| 8 | 133 |
| 9 | 334 |
| 10 | 839 |
| 11 | 2112 |
| 12 | 5329 |
| 13 | 13475 |
| 14 | 34143 |
| 15 | 86674 |
| 16 | 220400 |
| 17 | 561309 |
| 18 | 1431522 |
| 19 | 3655480 |
| 20 | 9345287 |
| 21 | 23916622 |
| 22 | 61267207 |
| 23 | 157088278 |
| 24 | 403103955 |
| 25 | 1035192885 |
| 26 | 2660312103 |
| 27 | 6841157380 |
| 28 | 17603254230 |
| 29 | 45321606641 |
| 30 | 116748360064 |