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 | 3 |
| 2 | 13 |
| 3 | 39 |
| 4 | 97 |
| 5 | 219 |
| 6 | 469 |
| 7 | 975 |
| 8 | 1993 |
| 9 | 4035 |
| 10 | 8125 |
| 11 | 16311 |
| 12 | 32689 |
| 13 | 65451 |
| 14 | 130981 |
| 15 | 262047 |
| 16 | 524185 |
| 17 | 1048467 |
| 18 | 2097037 |
| 19 | 4194183 |
| 20 | 8388481 |
| 21 | 16777083 |
| 22 | 33554293 |
| 23 | 67108719 |
| 24 | 134217577 |
| 25 | 268435299 |
| 26 | 536870749 |
| 27 | 1073741655 |
| 28 | 2147483473 |
| 29 | 4294967115 |
| 30 | 8589934405 |
| 31 | 17179868991 |