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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 51 |
| 6 | 141 |
| 7 | 393 |
| 8 | 1107 |
| 9 | 3139 |
| 10 | 8953 |
| 11 | 25653 |
| 12 | 73789 |
| 13 | 212941 |
| 14 | 616227 |
| 15 | 1787607 |
| 16 | 5196627 |
| 17 | 15134931 |
| 18 | 44152809 |
| 19 | 128996853 |
| 20 | 377379369 |
| 21 | 1105350729 |
| 22 | 3241135527 |
| 23 | 9513228123 |
| 24 | 27948336381 |
| 25 | 82176836301 |
| 26 | 241813226151 |
| 27 | 712070156203 |
| 28 | 2098240353907 |
| 29 | 6186675630819 |