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 | 502 |
| 10 | 1003 |
| 11 | 2003 |
| 12 | 3999 |
| 13 | 7983 |
| 14 | 15935 |
| 15 | 31807 |
| 16 | 63487 |
| 17 | 126719 |
| 18 | 252936 |
| 19 | 504869 |
| 20 | 1007735 |
| 21 | 2011471 |
| 22 | 4014959 |
| 23 | 8013983 |
| 24 | 15996159 |
| 25 | 31928831 |
| 26 | 63730943 |
| 27 | 127208950 |
| 28 | 253913031 |
| 29 | 506818327 |
| 30 | 1011625183 |
| 31 | 2019235407 |