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 | 2 |
| 3 | 4 |
| 4 | 18 |
| 5 | 76 |
| 6 | 420 |
| 7 | 2248 |
| 8 | 14410 |
| 9 | 89676 |
| 10 | 642764 |
| 11 | 4487896 |
| 12 | 35282228 |
| 13 | 271094936 |
| 14 | 2310824808 |
| 15 | 19309255952 |
| 16 | 177093587874 |
| 17 | 1596354765308 |
| 18 | 15664040851996 |
| 19 | 151403517122328 |
| 20 | 1582290415072396 |
| 21 | 16319413287176584 |
| 22 | 180949924453071544 |
| 23 | 1983128441367699632 |
| 24 | 23249895784026465044 |
| 25 | 269763155110100504568 |
| 26 | 3333619355332522429656 |