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 | 25 |
| 2 | 150 |
| 3 | 775 |
| 4 | 3900 |
| 5 | 19525 |
| 6 | 97650 |
| 7 | 488275 |
| 8 | 2441400 |
| 9 | 12207025 |
| 10 | 61035150 |
| 11 | 305175775 |
| 12 | 1525878900 |
| 13 | 7629394525 |
| 14 | 38146972650 |
| 15 | 190734863275 |
| 16 | 953674316400 |
| 17 | 4768371582025 |
| 18 | 23841857910150 |
| 19 | 119209289550775 |
| 20 | 596046447753900 |
| 21 | 2980232238769525 |