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 | 17 |
| 3 | 72 |
| 4 | 304 |
| 5 | 1284 |
| 6 | 5424 |
| 7 | 22912 |
| 8 | 96784 |
| 9 | 408832 |
| 10 | 1726976 |
| 11 | 7295040 |
| 12 | 30815488 |
| 13 | 130169856 |
| 14 | 549859584 |
| 15 | 2322700288 |
| 16 | 9811480576 |
| 17 | 41445360640 |
| 18 | 175072243712 |
| 19 | 739534897152 |
| 20 | 3123921031168 |
| 21 | 13195973099520 |
| 22 | 55742031986688 |
| 23 | 235463812071424 |
| 24 | 994639140683776 |