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 | 6 |
| 1 | 33 |
| 2 | 165 |
| 3 | 789 |
| 4 | 3669 |
| 5 | 16725 |
| 6 | 75093 |
| 7 | 333141 |
| 8 | 1463637 |
| 9 | 6378837 |
| 10 | 27612501 |
| 11 | 118838613 |
| 12 | 508908885 |
| 13 | 2169853269 |
| 14 | 9216283989 |
| 15 | 39012619605 |
| 16 | 164640413013 |
| 17 | 692921390421 |
| 18 | 2909124515157 |