An integer is divisible by this value if the (*) sum of its digits is also divisible by this number.
Odd numbers are multiplied by this value then added to one in the Collatz conjecture's computation. This value is the smallest Mersenne prime and the second triangular number. An integer is divisible by this value if the (*) sum of its digits is also divisible by this number. This value follows 1, 1, 2 in the Fibonacci sequence. For ten points, name this smallest odd prime number.
Odd numbers are multiplied by this value then added to one in the Collatz conjecture's computation.
three