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) |
|---|---|
| 3 | 1 |
| 4 | 10 |
| 5 | 68 |
| 6 | 396 |
| 7 | 2136 |
| 8 | 11062 |
| 9 | 56070 |
| 10 | 281306 |
| 11 | 1406721 |
| 12 | 7042818 |
| 13 | 35401568 |
| 14 | 178975192 |
| 15 | 910933936 |
| 16 | 4669860386 |
| 17 | 24114746282 |
| 18 | 125416122430 |
| 19 | 656713729000 |
| 20 | 3460748531510 |
| 21 | 18345703137458 |
| 22 | 97782896293158 |
| 23 | 523786141723670 |