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 | 1 |
| 1 | 5 |
| 2 | 26 |
| 3 | 135 |
| 4 | 700 |
| 5 | 3630 |
| 6 | 18825 |
| 7 | 97625 |
| 8 | 506275 |
| 9 | 2625500 |
| 10 | 13615625 |
| 11 | 70609500 |
| 12 | 366175000 |
| 13 | 1898953125 |
| 14 | 9847813125 |
| 15 | 51069940625 |
| 16 | 264844468750 |
| 17 | 1373461409375 |
| 18 | 7122656750000 |
| 19 | 36937506093750 |
| 20 | 191554837515625 |
| 21 | 993387471328125 |
| 22 | 5151624887109375 |
| 23 | 26715898623125000 |