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 | 5 |
| 2 | 18 |
| 3 | 68 |
| 4 | 264 |
| 5 | 1040 |
| 6 | 4128 |
| 7 | 16448 |
| 8 | 65664 |
| 9 | 262400 |
| 10 | 1049088 |
| 11 | 4195328 |
| 12 | 16779264 |
| 13 | 67112960 |
| 14 | 268443648 |
| 15 | 1073758208 |
| 16 | 4295000064 |
| 17 | 17179934720 |
| 18 | 68719607808 |
| 19 | 274878169088 |
| 20 | 1099512152064 |
| 21 | 4398047559680 |
| 22 | 17592188141568 |
| 23 | 70368748371968 |
| 24 | 281474985099264 |