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) |
|---|---|
| 1 | 0 |
| 2 | 8 |
| 3 | 24 |
| 4 | 112 |
| 5 | 560 |
| 6 | 2976 |
| 7 | 16464 |
| 8 | 94016 |
| 9 | 549648 |
| 10 | 3273040 |
| 11 | 19781168 |
| 12 | 121020960 |
| 13 | 748039552 |
| 14 | 4664263744 |
| 15 | 29303071680 |
| 16 | 185307690240 |
| 17 | 1178635456752 |
| 18 | 7535046744864 |
| 19 | 48392012257184 |
| 20 | 312061600211680 |
| 21 | 2019822009608592 |
| 22 | 13117263660884768 |
| 23 | 85447982919036736 |