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 | 25 |
| 2 | 123 |
| 3 | 727 |
| 4 | 4911 |
| 5 | 35935 |
| 6 | 274623 |
| 7 | 2146687 |
| 8 | 16974591 |
| 9 | 135005695 |
| 10 | 1076890623 |
| 11 | 8602523647 |
| 12 | 68769820671 |
| 13 | 549957165055 |
| 14 | 4398851866623 |
| 15 | 35187593412607 |
| 16 | 281487861809151 |
| 17 | 2251851353686015 |
| 18 | 18014604668698623 |
| 19 | 144116012711149567 |
| 20 | 1152924803144876031 |