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 | 2 |
| 1 | 13 |
| 2 | 59 |
| 3 | 247 |
| 4 | 1007 |
| 5 | 4063 |
| 6 | 16319 |
| 7 | 65407 |
| 8 | 261887 |
| 9 | 1048063 |
| 10 | 4193279 |
| 11 | 16775167 |
| 12 | 67104767 |
| 13 | 268427263 |
| 14 | 1073725439 |
| 15 | 4294934527 |
| 16 | 17179803647 |
| 17 | 68719345663 |
| 18 | 274877644799 |
| 19 | 1099511103487 |
| 20 | 4398045462527 |
| 21 | 17592183947263 |
| 22 | 70368739983359 |
| 23 | 281474968322047 |
| 24 | 1125899890065407 |