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 | 3 |
| 4 | 31 |
| 5 | 252 |
| 6 | 1776 |
| 7 | 11048 |
| 8 | 61106 |
| 9 | 303664 |
| 10 | 1368844 |
| 11 | 5651241 |
| 12 | 21559133 |
| 13 | 76613440 |
| 14 | 255411923 |
| 15 | 803771681 |
| 16 | 2400633464 |
| 17 | 6837010458 |
| 18 | 18644075466 |
| 19 | 48855805143 |
| 20 | 123415815229 |
| 21 | 301386128354 |
| 22 | 713271875603 |
| 23 | 1639572164669 |
| 24 | 3667859207856 |