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 | 0 |
| 1 | 4 |
| 2 | 32 |
| 3 | 164 |
| 4 | 704 |
| 5 | 2716 |
| 6 | 9808 |
| 7 | 33788 |
| 8 | 112480 |
| 9 | 364588 |
| 10 | 1157296 |
| 11 | 3610884 |
| 12 | 11108448 |
| 13 | 33765276 |
| 14 | 101594000 |
| 15 | 302977204 |
| 16 | 896627936 |
| 17 | 2635423124 |
| 18 | 7699729296 |
| 19 | 22374323436 |
| 20 | 64702914336 |
| 21 | 186289216332 |
| 22 | 534227118960 |
| 23 | 1526445330900 |
| 24 | 4347038392480 |
| 25 | 12341626847324 |
| 26 | 34940293640400 |
| 27 | 98660244502668 |