How many 4-digit positive integers are there, where each digit is positive…

How many 4-digit positive integers are there, where each digit is positive, and no 3 adjacent digits are same?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #23339