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 | 1 |
| 3 | 4 |
| 4 | 19 |
| 5 | 91 |
| 6 | 476 |
| 7 | 2586 |
| 8 | 14421 |
| 9 | 82225 |
| 10 | 476913 |
| 11 | 2804880 |
| 12 | 16689036 |
| 13 | 100276894 |
| 14 | 607588840 |
| 15 | 3708251888 |
| 16 | 22776251835 |
| 17 | 140676848445 |
| 18 | 873210347555 |
| 19 | 5444307431052 |
| 20 | 34080036632565 |
| 21 | 214104150405915 |
| 22 | 1349504948018208 |
| 23 | 8531467913710560 |
| 24 | 54083412667272300 |
| 25 | 343715994386622918 |
| 26 | 2189505804590364876 |