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 | 1 |
| 2 | 6 |
| 3 | 27 |
| 4 | 132 |
| 5 | 629 |
| 6 | 3162 |
| 7 | 15631 |
| 8 | 78264 |
| 9 | 390681 |
| 10 | 1953774 |
| 11 | 9765635 |
| 12 | 48831564 |
| 13 | 244140637 |
| 14 | 1220718786 |
| 15 | 6103516983 |
| 16 | 30517656528 |
| 17 | 152587890641 |
| 18 | 762939850086 |
| 19 | 3814697265643 |
| 20 | 19073488283028 |
| 21 | 95367431672037 |
| 22 | 476837167968810 |
| 23 | 2384185791015647 |
| 24 | 11920929004069128 |