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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 6 |
| 8 | 18 |
| 9 | 66 |
| 10 | 208 |
| 11 | 646 |
| 12 | 1962 |
| 13 | 5962 |
| 14 | 18014 |
| 15 | 54578 |
| 16 | 165650 |
| 17 | 504220 |
| 18 | 1539330 |
| 19 | 4713742 |
| 20 | 14475936 |
| 21 | 44578668 |
| 22 | 137634872 |
| 23 | 425970290 |
| 24 | 1321323952 |
| 25 | 4107268140 |
| 26 | 12792332438 |
| 27 | 39915708564 |
| 28 | 124762612530 |
| 29 | 390593588402 |
| 30 | 1224681912368 |
| 31 | 3845387953884 |
| 32 | 12090382743374 |