HP Prime Program: ULAM
Message #1 Posted by Eddie W. Shore on 2 Oct 2013, 3:34 p.m.
ULAM - Using Ulam's Conjecture to determine the number of steps it takes to reduce an integer N to 1 using the following rules:
If N is odd: N = 3ŚN+1
If N is even: N=N/2
9/24/2013
Program:
EXPORT ULAM(N)
BEGIN
LOCAL C;
PRINT();
REPEAT
IF FP(N/2)==0 THEN
N:=N/2;
ELSE
N:=3*N+1;
END;
C:=C+1;
PRINT(N);
UNTIL N==1;
RETURN C;
END;
Examples:
ULAM(69): 208, 104, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1 (14 steps)
ULAM(84): 42, 21, 64, 32, 16, 8, 4, 2, 1 (9 steps)
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