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 | 20 |
| 3 | 125 |
| 4 | 610 |
| 5 | 2611 |
| 6 | 10815 |
| 7 | 42610 |
| 8 | 161005 |
| 9 | 590155 |
| 10 | 2106362 |
| 11 | 7348265 |
| 12 | 25141430 |
| 13 | 84569395 |
| 14 | 280246795 |
| 15 | 916465742 |
| 16 | 2961805180 |
| 17 | 9470735650 |
| 18 | 29994694130 |
| 19 | 94172180660 |
| 20 | 293326457342 |
| 21 | 907028460410 |
| 22 | 2786036875580 |
| 23 | 8505001839950 |
| 24 | 25815678641935 |
| 25 | 77945771624609 |