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 | 2 |
| 2 | 6 |
| 3 | 21 |
| 4 | 65 |
| 5 | 183 |
| 6 | 543 |
| 7 | 1587 |
| 8 | 4685 |
| 9 | 13935 |
| 10 | 41708 |
| 11 | 125479 |
| 12 | 379317 |
| 13 | 1150971 |
| 14 | 3503790 |
| 15 | 10695879 |
| 16 | 32729271 |
| 17 | 100361001 |
| 18 | 308313167 |
| 19 | 948694965 |