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 | 4 |
| 2 | 84 |
| 3 | 318 |
| 4 | 1328 |
| 5 | 6064 |
| 6 | 26918 |
| 7 | 116909 |
| 8 | 511264 |
| 9 | 2248196 |
| 10 | 9868600 |
| 11 | 43259517 |
| 12 | 189716276 |
| 13 | 832295019 |
| 14 | 3650903623 |
| 15 | 16013507645 |
| 16 | 70240174360 |
| 17 | 308101760364 |
| 18 | 1351448959786 |
| 19 | 5927927566218 |
| 20 | 26002016887928 |
| 21 | 114054342072628 |