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 | 3 |
| 2 | 6 |
| 3 | 21 |
| 4 | 87 |
| 5 | 363 |
| 6 | 1491 |
| 7 | 6051 |
| 8 | 24387 |
| 9 | 97923 |
| 10 | 392451 |
| 11 | 1571331 |
| 12 | 6288387 |
| 13 | 25159683 |
| 14 | 100651011 |
| 15 | 402628611 |
| 16 | 1610563587 |
| 17 | 6442352643 |
| 18 | 25769607171 |
| 19 | 103078821891 |
| 20 | 412316073987 |
| 21 | 1649265868803 |
| 22 | 6597066620931 |