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 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 20 |
| 6 | 44 |
| 7 | 92 |
| 8 | 194 |
| 9 | 396 |
| 10 | 820 |
| 11 | 1684 |
| 12 | 3432 |
| 13 | 6972 |
| 14 | 14144 |
| 15 | 28636 |
| 16 | 57890 |
| 17 | 116828 |
| 18 | 235500 |
| 19 | 474304 |
| 20 | 954444 |
| 21 | 1919364 |
| 22 | 3857548 |
| 23 | 7748888 |
| 24 | 15558988 |
| 25 | 31229384 |
| 26 | 62662088 |
| 27 | 125696800 |
| 28 | 252079196 |
| 29 | 505423476 |
| 30 | 1013189208 |
| 31 | 2030729700 |
| 32 | 4069562810 |
| 33 | 8154257184 |
| 34 | 16336840080 |
| 35 | 32726819744 |
| 36 | 65553540096 |