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 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 21 |
| 6 | 48 |
| 7 | 120 |
| 8 | 309 |
| 9 | 787 |
| 10 | 2011 |
| 11 | 5215 |
| 12 | 13652 |
| 13 | 35894 |
| 14 | 94823 |
| 15 | 251889 |
| 16 | 672285 |
| 17 | 1801185 |
| 18 | 4842757 |
| 19 | 13064059 |
| 20 | 35349463 |
| 21 | 95912989 |
| 22 | 260896318 |
| 23 | 711338596 |
| 24 | 1943690464 |
| 25 | 5321704006 |
| 26 | 14597781706 |
| 27 | 40112702176 |
| 28 | 110404515703 |
| 29 | 304338523999 |
| 30 | 840140172621 |
| 31 | 2322386563353 |