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 | 9 |
| 3 | 45 |
| 4 | 225 |
| 5 | 1125 |
| 6 | 5625 |
| 7 | 28125 |
| 8 | 140625 |
| 9 | 703125 |
| 10 | 3515625 |
| 11 | 17578125 |
| 12 | 87890625 |
| 13 | 439453125 |
| 14 | 2197265625 |
| 15 | 10986328125 |
| 16 | 54931640625 |
| 17 | 274658203125 |
| 18 | 1373291015625 |
| 19 | 6866455078125 |
| 20 | 34332275390625 |
| 21 | 171661376953125 |
| 22 | 858306884765625 |
| 23 | 4291534423828125 |
| 24 | 21457672119140625 |