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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 17 |
| 4 | 72 |
| 5 | 305 |
| 6 | 1292 |
| 7 | 5473 |
| 8 | 23184 |
| 9 | 98209 |
| 10 | 416020 |
| 11 | 1762289 |
| 12 | 7465176 |
| 13 | 31622993 |
| 14 | 133957148 |
| 15 | 567451585 |
| 16 | 2403763488 |
| 17 | 10182505537 |
| 18 | 43133785636 |
| 19 | 182717648081 |
| 20 | 774004377960 |
| 21 | 3278735159921 |
| 22 | 13888945017644 |
| 23 | 58834515230497 |
| 24 | 249227005939632 |
| 25 | 1055742538989025 |