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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 0 |
| 7 | 0 |
| 8 | 1 |
| 9 | 2 |
| 10 | 4 |
| 11 | 8 |
| 12 | 16 |
| 13 | 32 |
| 14 | 63 |
| 15 | 126 |
| 16 | 252 |
| 17 | 503 |
| 18 | 1004 |
| 19 | 2004 |
| 20 | 4000 |
| 21 | 7984 |
| 22 | 15936 |
| 23 | 31809 |
| 24 | 63492 |
| 25 | 126732 |
| 26 | 252961 |
| 27 | 504918 |
| 28 | 1007832 |
| 29 | 2011664 |
| 30 | 4015344 |
| 31 | 8014752 |
| 32 | 15997695 |
| 33 | 31931898 |
| 34 | 63737064 |
| 35 | 127221167 |
| 36 | 253937416 |
| 37 | 506867000 |
| 38 | 1011722336 |
| 39 | 2019429328 |