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 | 5 |
| 2 | 17 |
| 3 | 69 |
| 4 | 257 |
| 5 | 997 |
| 6 | 3793 |
| 7 | 14565 |
| 8 | 55681 |
| 9 | 213317 |
| 10 | 816401 |
| 11 | 3126021 |
| 12 | 11966849 |
| 13 | 45815845 |
| 14 | 175399633 |
| 15 | 671510181 |
| 16 | 2570817793 |
| 17 | 9842206853 |
| 18 | 37680138257 |
| 19 | 144255724485 |
| 20 | 552272416769 |
| 21 | 2114334904933 |
| 22 | 8094576727249 |
| 23 | 30989497789029 |