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 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 41 |
| 5 | 134 |
| 6 | 471 |
| 7 | 1819 |
| 8 | 7778 |
| 9 | 36703 |
| 10 | 189381 |
| 11 | 1057332 |
| 12 | 6328261 |
| 13 | 40300959 |
| 14 | 271501240 |
| 15 | 1925961025 |
| 16 | 14332064197 |
| 17 | 111528998198 |
| 18 | 905134802555 |
| 19 | 7643011810167 |
| 20 | 67010181855706 |
| 21 | 608890179868163 |
| 22 | 5724496098183649 |