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) |
|---|---|
| 3 | 1 |
| 4 | 9 |
| 5 | 57 |
| 6 | 298 |
| 7 | 1545 |
| 8 | 7126 |
| 9 | 34603 |
| 10 | 151633 |
| 11 | 714481 |
| 12 | 3049328 |
| 13 | 14131926 |
| 14 | 59385159 |
| 15 | 272409611 |
| 16 | 1133433579 |
| 17 | 5163641033 |
| 18 | 21341122875 |
| 19 | 96751092786 |
| 20 | 397978832144 |
| 21 | 1797722306693 |
| 22 | 7369285976135 |
| 23 | 33195299823112 |
| 24 | 135723491400062 |
| 25 | 610027809595308 |
| 26 | 2489247495517382 |
| 27 | 11168400384253936 |