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 | 4 |
| 3 | 16 |
| 4 | 61 |
| 5 | 225 |
| 6 | 815 |
| 7 | 2923 |
| 8 | 10428 |
| 9 | 37097 |
| 10 | 131776 |
| 11 | 467732 |
| 12 | 1659537 |
| 13 | 5886945 |
| 14 | 20880912 |
| 15 | 74060619 |
| 16 | 262672473 |
| 17 | 931615218 |
| 18 | 3304121816 |
| 19 | 11718561425 |
| 20 | 41561571533 |