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 | 7 |
| 2 | 21 |
| 3 | 70 |
| 4 | 245 |
| 5 | 882 |
| 6 | 3234 |
| 7 | 12012 |
| 8 | 45045 |
| 9 | 170170 |
| 10 | 646646 |
| 11 | 2469012 |
| 12 | 9464546 |
| 13 | 36402100 |
| 14 | 140408100 |
| 15 | 542911320 |
| 16 | 2103781365 |
| 17 | 8167621770 |
| 18 | 31762973550 |
| 19 | 123708423300 |
| 20 | 482462850870 |
| 21 | 1883902560540 |
| 22 | 7364346373020 |
| 23 | 28817007546600 |
| 24 | 112866612890850 |
| 25 | 442437122532132 |
| 26 | 1735714865318364 |