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 | 25 |
| 2 | 625 |
| 3 | 1250 |
| 4 | 2500 |
| 5 | 10000 |
| 6 | 40000 |
| 7 | 145200 |
| 8 | 527076 |
| 9 | 2056032 |
| 10 | 8020224 |
| 11 | 29854944 |
| 12 | 111133764 |
| 13 | 429565416 |
| 14 | 1660399504 |
| 15 | 6232977072 |
| 16 | 23397985296 |
| 17 | 90031551120 |
| 18 | 346426416400 |
| 19 | 1306080208880 |
| 20 | 4924120769296 |
| 21 | 18891767424072 |
| 22 | 72479716304004 |