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) |
|---|---|
| 3 | 240 |
| 4 | 816 |
| 5 | 2400 |
| 6 | 6480 |
| 7 | 16660 |
| 8 | 41440 |
| 9 | 100836 |
| 10 | 241520 |
| 11 | 571692 |
| 12 | 1340832 |
| 13 | 3121456 |
| 14 | 7222040 |
| 15 | 16622220 |
| 16 | 38085312 |
| 17 | 86918688 |
| 18 | 197677368 |
| 19 | 448182640 |
| 20 | 1013320480 |
| 21 | 2285339532 |
| 22 | 5142429512 |
| 23 | 11547488652 |
| 24 | 25881229248 |
| 25 | 57906534100 |
| 26 | 129352490384 |
| 27 | 288522099360 |
| 28 | 642668803056 |
| 29 | 1429687270740 |
| 30 | 3176714397960 |