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 | 13 |
| 2 | 169 |
| 3 | 699 |
| 4 | 2920 |
| 5 | 14446 |
| 6 | 63031 |
| 7 | 258952 |
| 8 | 1088966 |
| 9 | 4519672 |
| 10 | 18366772 |
| 11 | 74473407 |
| 12 | 301250239 |
| 13 | 1211354604 |
| 14 | 4857059037 |
| 15 | 19448559879 |
| 16 | 77732455665 |
| 17 | 310249629843 |
| 18 | 1237296397590 |
| 19 | 4930959447666 |
| 20 | 19639536330789 |
| 21 | 78190784495920 |