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 | 6 |
| 2 | 40 |
| 3 | 272 |
| 4 | 1856 |
| 5 | 12672 |
| 6 | 86528 |
| 7 | 590848 |
| 8 | 4034560 |
| 9 | 27549696 |
| 10 | 188121088 |
| 11 | 1284571136 |
| 12 | 8771600384 |
| 13 | 59896233984 |
| 14 | 408997068800 |
| 15 | 2792806678528 |
| 16 | 19070476877824 |
| 17 | 130221361594368 |
| 18 | 889207077732352 |
| 19 | 6071885729103872 |
| 20 | 41461429210972160 |
| 21 | 283116347854946304 |
| 22 | 1933239349151793152 |