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 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 54 |
| 5 | 213 |
| 6 | 880 |
| 7 | 3724 |
| 8 | 16143 |
| 9 | 71227 |
| 10 | 319067 |
| 11 | 1447160 |
| 12 | 6633530 |
| 13 | 30682425 |
| 14 | 143028870 |
| 15 | 671293632 |
| 16 | 3169572659 |
| 17 | 15044993968 |
| 18 | 71752624923 |
| 19 | 343658572717 |
| 20 | 1652266087698 |
| 21 | 7971518032791 |
| 22 | 38581202763318 |
| 23 | 187269381724629 |
| 24 | 911404238805468 |
| 25 | 4446493502832481 |
| 26 | 21742327471261176 |