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 | 3 |
| 2 | 9 |
| 3 | 36 |
| 4 | 165 |
| 5 | 768 |
| 6 | 4212 |
| 7 | 24573 |
| 8 | 146949 |
| 9 | 994608 |
| 10 | 6824064 |
| 11 | 49026783 |
| 12 | 382079820 |
| 13 | 3012960603 |
| 14 | 24957495705 |
| 15 | 216087717621 |
| 16 | 1931094309909 |
| 17 | 17705427261168 |
| 18 | 169400058948720 |
| 19 | 1679587464655155 |
| 20 | 16724057142118920 |
| 21 | 174698022293109813 |
| 22 | 1876447876721132955 |