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 | 5 |
| 2 | 15 |
| 3 | 35 |
| 4 | 120 |
| 5 | 201 |
| 6 | 1505 |
| 7 | 2015 |
| 8 | 14070 |
| 9 | 37085 |
| 10 | 246753 |
| 11 | 445515 |
| 12 | 5205790 |
| 13 | 7832185 |
| 14 | 72703645 |
| 15 | 254689657 |
| 16 | 1196213445 |
| 17 | 2805046965 |
| 18 | 35322811755 |
| 19 | 55770979195 |
| 20 | 596439735024 |
| 21 | 1892294578755 |
| 22 | 10837223014665 |
| 23 | 23559159229935 |
| 24 | 310484619147940 |
| 25 | 596046508875701 |
| 26 | 4776013513099405 |
| 27 | 15330413466776835 |
| 28 | 110874578286500410 |