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 | 4 |
| 2 | 16 |
| 3 | 61 |
| 4 | 232 |
| 5 | 880 |
| 6 | 3337 |
| 7 | 12652 |
| 8 | 47968 |
| 9 | 181861 |
| 10 | 689488 |
| 11 | 2614048 |
| 12 | 9910609 |
| 13 | 37573972 |
| 14 | 142453744 |
| 15 | 540083149 |
| 16 | 2047610680 |
| 17 | 7763081488 |
| 18 | 29432076505 |
| 19 | 111585473980 |
| 20 | 423052651456 |
| 21 | 1603914376309 |
| 22 | 6080901083296 |
| 23 | 23054446378816 |