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) |
|---|---|
| 2 | 20 |
| 3 | 100 |
| 4 | 420 |
| 5 | 1694 |
| 6 | 6746 |
| 7 | 26735 |
| 8 | 105722 |
| 9 | 417613 |
| 10 | 1648692 |
| 11 | 6507197 |
| 12 | 25681362 |
| 13 | 101359219 |
| 14 | 400094756 |
| 15 | 1579568360 |
| 16 | 6237401648 |
| 17 | 24635828774 |
| 18 | 97327071806 |
| 19 | 384596629610 |
| 20 | 1520138671688 |
| 21 | 6009885957464 |
| 22 | 23765835521966 |
| 23 | 94003008751940 |