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 | 0 |
| 2 | 6 |
| 3 | 12 |
| 4 | 54 |
| 5 | 216 |
| 6 | 1032 |
| 7 | 4896 |
| 8 | 24606 |
| 9 | 125040 |
| 10 | 651348 |
| 11 | 3432168 |
| 12 | 18331992 |
| 13 | 98814816 |
| 14 | 537343632 |
| 15 | 2942475552 |
| 16 | 16214888286 |
| 17 | 89835783264 |
| 18 | 500116783740 |
| 19 | 2795958732024 |
| 20 | 15690597591636 |
| 21 | 88354191756816 |
| 22 | 499060719941616 |
| 23 | 2826794871554112 |
| 24 | 16052536475622792 |