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 | 8 |
| 2 | 55 |
| 3 | 377 |
| 4 | 2584 |
| 5 | 17711 |
| 6 | 121393 |
| 7 | 832040 |
| 8 | 5702887 |
| 9 | 39088169 |
| 10 | 267914296 |
| 11 | 1836311903 |
| 12 | 12586269025 |
| 13 | 86267571272 |
| 14 | 591286729879 |
| 15 | 4052739537881 |
| 16 | 27777890035288 |
| 17 | 190392490709135 |
| 18 | 1304969544928657 |
| 19 | 8944394323791464 |
| 20 | 61305790721611591 |
| 21 | 420196140727489673 |