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 | 16 |
| 3 | 128 |
| 4 | 448 |
| 5 | 2256 |
| 6 | 5376 |
| 7 | 29424 |
| 8 | 69888 |
| 9 | 302568 |
| 10 | 741376 |
| 11 | 3026448 |
| 12 | 7216896 |
| 13 | 29268352 |
| 14 | 65785216 |
| 15 | 263892736 |
| 16 | 591065568 |
| 17 | 2279452040 |
| 18 | 5195776064 |
| 19 | 19324558176 |
| 20 | 44442289024 |
| 21 | 161417689504 |
| 22 | 371206519136 |
| 23 | 1328055630144 |
| 24 | 3044451252064 |
| 25 | 10774811055304 |
| 26 | 24625495784320 |
| 27 | 86363375773808 |
| 28 | 197092099990080 |