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 | 21 |
| 2 | 654 |
| 3 | 13937 |
| 4 | 340825 |
| 5 | 8273245 |
| 6 | 200646607 |
| 7 | 4869858862 |
| 8 | 118156684121 |
| 9 | 2867120332406 |
| 10 | 69570025944705 |
| 11 | 1688108287602302 |
| 12 | 40961748924233513 |
| 13 | 993931518658886393 |
| 14 | 24117625902266425892 |
| 15 | 585211158099440381626 |