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 | 4 |
| 2 | 12 |
| 3 | 40 |
| 4 | 112 |
| 5 | 352 |
| 6 | 832 |
| 7 | 2176 |
| 8 | 4864 |
| 9 | 11776 |
| 10 | 29696 |
| 11 | 63488 |
| 12 | 151552 |
| 13 | 335872 |
| 14 | 704512 |
| 15 | 1540096 |
| 16 | 3473408 |
| 17 | 7733248 |
| 18 | 15990784 |
| 19 | 35127296 |
| 20 | 74448896 |
| 21 | 153092096 |
| 22 | 331350016 |
| 23 | 696254464 |
| 24 | 1493172224 |
| 25 | 3254779904 |
| 26 | 6777995264 |
| 27 | 13824425984 |
| 28 | 28722593792 |
| 29 | 58518929408 |
| 30 | 121332826112 |