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 | 3 |
| 2 | 11 |
| 3 | 52 |
| 4 | 252 |
| 5 | 1253 |
| 6 | 6253 |
| 7 | 31254 |
| 8 | 156254 |
| 9 | 781255 |
| 10 | 3906255 |
| 11 | 19531256 |
| 12 | 97656256 |
| 13 | 488281257 |
| 14 | 2441406257 |
| 15 | 12207031258 |
| 16 | 61035156258 |
| 17 | 305175781259 |
| 18 | 1525878906259 |
| 19 | 7629394531260 |
| 20 | 38146972656260 |
| 21 | 190734863281261 |
| 22 | 953674316406261 |
| 23 | 4768371582031262 |
| 24 | 23841857910156262 |