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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 12 |
| 4 | 49 |
| 5 | 195 |
| 6 | 780 |
| 7 | 3121 |
| 8 | 12483 |
| 9 | 49932 |
| 10 | 199729 |
| 11 | 798915 |
| 12 | 3195660 |
| 13 | 12782641 |
| 14 | 51130563 |
| 15 | 204522252 |
| 16 | 818089009 |
| 17 | 3272356035 |
| 18 | 13089424140 |
| 19 | 52357696561 |
| 20 | 209430786243 |
| 21 | 837723144972 |
| 22 | 3350892579889 |
| 23 | 13403570319555 |
| 24 | 53614281278220 |
| 25 | 214457125112881 |