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 | 39 |
| 3 | 203 |
| 4 | 1040 |
| 5 | 5313 |
| 6 | 27133 |
| 7 | 138565 |
| 8 | 707643 |
| 9 | 3613904 |
| 10 | 18456077 |
| 11 | 94254531 |
| 12 | 481354555 |
| 13 | 2458260679 |
| 14 | 12554250288 |
| 15 | 64114111901 |
| 16 | 327428500337 |
| 17 | 1672165762785 |
| 18 | 8539691368807 |
| 19 | 43611901581472 |
| 20 | 222724437852585 |