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 | 5 |
| 3 | 31 |
| 4 | 201 |
| 5 | 1206 |
| 6 | 6751 |
| 7 | 36051 |
| 8 | 187025 |
| 9 | 954136 |
| 10 | 4822527 |
| 11 | 24251877 |
| 12 | 121631329 |
| 13 | 609151986 |
| 14 | 3048441935 |
| 15 | 15249510871 |
| 16 | 76267672545 |
| 17 | 381394509228 |
| 18 | 1907131201327 |
| 19 | 9536109476745 |
| 20 | 47681856564305 |
| 21 | 238413094649734 |
| 22 | 1192076649237855 |
| 23 | 5960416195898811 |