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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 15 |
| 5 | 31 |
| 6 | 63 |
| 7 | 127 |
| 8 | 255 |
| 9 | 511 |
| 10 | 1013 |
| 11 | 2025 |
| 12 | 4047 |
| 13 | 8087 |
| 14 | 16159 |
| 15 | 32287 |
| 16 | 64511 |
| 17 | 128895 |
| 18 | 257535 |
| 19 | 514559 |
| 20 | 1028105 |
| 21 | 2054185 |
| 22 | 4104323 |
| 23 | 8200559 |
| 24 | 16384959 |
| 25 | 32737631 |
| 26 | 65410751 |
| 27 | 130692607 |
| 28 | 261127679 |
| 29 | 521740799 |
| 30 | 1042453493 |
| 31 | 2082852801 |