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 | 5 |
| 1 | 15 |
| 2 | 55 |
| 3 | 225 |
| 4 | 979 |
| 5 | 4425 |
| 6 | 20515 |
| 7 | 96825 |
| 8 | 462979 |
| 9 | 2235465 |
| 10 | 10874275 |
| 11 | 53201625 |
| 12 | 261453379 |
| 13 | 1289414505 |
| 14 | 6376750435 |
| 15 | 31605701625 |
| 16 | 156925970179 |
| 17 | 780248593545 |
| 18 | 3883804424995 |
| 19 | 19349527020825 |
| 20 | 96470431101379 |
| 21 | 481245667164585 |
| 22 | 2401809362313955 |
| 23 | 11991391850823225 |