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 | 1 |
| 2 | 101 |
| 3 | 1 |
| 4 | 10101 |
| 5 | 10001 |
| 6 | 1000101 |
| 7 | 1 |
| 8 | 100010101 |
| 9 | 100010001 |
| 10 | 10101000101 |
| 11 | 100000001 |
| 12 | 1010000010101 |
| 13 | 1000000010001 |
| 14 | 100000001000101 |
| 15 | 1 |
| 16 | 10000000100010101 |
| 17 | 10000000100010001 |
| 18 | 1010000010101000101 |
| 19 | 10000000100000001 |
| 20 | 101010001010000010101 |
| 21 | 100010001000000010001 |