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 | 2 |
| 2 | 4 |
| 3 | 9 |
| 4 | 22 |
| 5 | 56 |
| 6 | 145 |
| 7 | 378 |
| 8 | 988 |
| 9 | 2585 |
| 10 | 6766 |
| 11 | 17712 |
| 12 | 46369 |
| 13 | 121394 |
| 14 | 317812 |
| 15 | 832041 |
| 16 | 2178310 |
| 17 | 5702888 |
| 18 | 14930353 |
| 19 | 39088170 |
| 20 | 102334156 |
| 21 | 267914297 |
| 22 | 701408734 |
| 23 | 1836311904 |
| 24 | 4807526977 |
| 25 | 12586269026 |
| 26 | 32951280100 |
| 27 | 86267571273 |