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 | 24 |
| 3 | 117 |
| 4 | 576 |
| 5 | 2821 |
| 6 | 13824 |
| 7 | 67723 |
| 8 | 331776 |
| 9 | 1625363 |
| 10 | 7962624 |
| 11 | 39008731 |
| 12 | 191102976 |
| 13 | 936209559 |
| 14 | 4586471424 |
| 15 | 22469029417 |
| 16 | 110075314176 |
| 17 | 539256706015 |
| 18 | 2641807540224 |
| 19 | 12942160944371 |
| 20 | 63403380965376 |