

A094669


Number of halving and tripling steps for 10^n to reach 1 in '3x+1' problem.


1



6, 25, 111, 29, 128, 152, 145, 107, 100, 124, 347, 146, 289, 194, 275, 255, 235, 303, 340, 470, 357, 324, 454, 266, 564, 433, 470, 331, 492, 467, 584, 515, 614, 550, 711, 497, 653, 1039, 577, 694, 749, 755, 779, 666, 752, 913, 769, 754, 724, 691, 883, 827, 683
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OFFSET

1,1


LINKS



FORMULA



PROG

(Python)
def f(x): return x//2 if x%2 == 0 else 3*x + 1
def a(n):
i, c = 10**n, 0
while i != 1: i, c = f(i), c+1
return c


CROSSREFS



KEYWORD

easy,nonn


AUTHOR



EXTENSIONS



STATUS

approved



