The first 4 terms 4, 7, 19, 67, ..., 1027 seem to follow the rule:
7=4+3, 19=7+4×3, 67=19+4×4×3, making the next term 67+4×4×4×3=259.
If we continue with this apparent rule, the next term is: 259+256×3=1027.
The series follows the proposed rule:
4, 7, 19, 67, 259, 1027; differences:
3, 12, 48, 192, 768.