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 | 6 |
| 3 | 19 |
| 4 | 76 |
| 5 | 261 |
| 6 | 1074 |
| 7 | 4103 |
| 8 | 16536 |
| 9 | 65593 |
| 10 | 262686 |
| 11 | 1048587 |
| 12 | 4196644 |
| 13 | 16777229 |
| 14 | 67117098 |
| 15 | 268436319 |
| 16 | 1073774896 |
| 17 | 4294967313 |
| 18 | 17180003478 |
| 19 | 68719476755 |
| 20 | 274878432636 |
| 21 | 1099511640197 |
| 22 | 4398048608322 |
| 23 | 17592186044439 |
| 24 | 70368752620104 |
| 25 | 281474976711961 |
| 26 | 1125899940397134 |