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 | 9 |
| 4 | 44 |
| 5 | 249 |
| 6 | 1506 |
| 7 | 9687 |
| 8 | 64803 |
| 9 | 447666 |
| 10 | 3169566 |
| 11 | 22897260 |
| 12 | 168168164 |
| 13 | 1252391041 |
| 14 | 9437809359 |
| 15 | 71850420813 |
| 16 | 551876468717 |
| 17 | 4272100488830 |
| 18 | 33299732401378 |
| 19 | 261165251593743 |
| 20 | 2059638535690473 |
| 21 | 16324255856903830 |
| 22 | 129969379170062142 |
| 23 | 1039056925387672998 |