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 | 5 |
| 2 | 19 |
| 3 | 73 |
| 4 | 302 |
| 5 | 1325 |
| 6 | 6032 |
| 7 | 28193 |
| 8 | 134825 |
| 9 | 659011 |
| 10 | 3290110 |
| 11 | 16764206 |
| 12 | 87103106 |
| 13 | 461090076 |
| 14 | 2484768459 |
| 15 | 13621130998 |
| 16 | 75906831145 |
| 17 | 429768775851 |
| 18 | 2470872560536 |
| 19 | 14418770507660 |
| 20 | 85367306874021 |
| 21 | 512604419523512 |