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) |
|---|---|
| 4 | 1 |
| 5 | 5 |
| 6 | 21 |
| 7 | 80 |
| 8 | 287 |
| 9 | 993 |
| 10 | 3347 |
| 11 | 11067 |
| 12 | 36055 |
| 13 | 116089 |
| 14 | 370222 |
| 15 | 1171353 |
| 16 | 3681375 |
| 17 | 11504101 |
| 18 | 35772799 |
| 19 | 110760185 |
| 20 | 341640131 |
| 21 | 1050254568 |
| 22 | 3218970519 |
| 23 | 9839399805 |
| 24 | 30002862947 |
| 25 | 91284474775 |
| 26 | 277176264351 |
| 27 | 840067321393 |
| 28 | 2541769382014 |
| 29 | 7678558044741 |
| 30 | 23163047559031 |