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 | 51 |
| 3 | 393 |
| 4 | 3139 |
| 5 | 25653 |
| 6 | 212941 |
| 7 | 1787607 |
| 8 | 15134931 |
| 9 | 128996853 |
| 10 | 1105350729 |
| 11 | 9513228123 |
| 12 | 82176836301 |
| 13 | 712070156203 |
| 14 | 6186675630819 |
| 15 | 53876592856681 |
| 16 | 470139239360787 |
| 17 | 4109922421017093 |
| 18 | 35986168879543609 |
| 19 | 315544068167601787 |
| 20 | 2770417140954208377 |
| 21 | 24352194654450483759 |