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A375909 Number of iterations of the Farkas map (A349407) to reach 1 starting from 2*n - 1.

%I A375909 #20 Sep 13 2024 08:00:35
%S A375909 0,1,2,5,2,4,6,3,3,5,6,6,7,3,4,9,5,5,6,7,7,7,4,8,8,4,4,10,6,6,10,7,6,
%T A375909 6,7,7,7,8,8,9,4,9,8,5,5,9,10,10,9,6,5,11,6,6,11,7,7,7,8,8,11,8,8,13,
%U A375909 8,8,7,5,8,8,9,9,8,9,9,10,5,10,10,5,5,10,11,11,9
%N A375909 Number of iterations of the Farkas map (A349407) to reach 1 starting from 2*n - 1.
%H A375909 Paolo Xausa, <a href="/A375909/b375909.txt">Table of n, a(n) for n = 1..10000</a>
%e A375909 a(10) = 5 because the trajectory 19 -> 29 -> 15 -> 5 -> 3 -> 1 takes 5 steps.
%t A375909 FarkasStep[x_] := Which[Divisible[x, 3], x/3, Mod[x, 4] == 3, (3*x + 1)/2, True, (x + 1)/2];
%t A375909 Array[Length[FixedPointList[FarkasStep, 2*# - 1]] - 2 &, 100]
%Y A375909 (Row lengths of A350279) - 1.
%Y A375909 Cf. A006577, A006666, A349407, A375267, A375911.
%K A375909 nonn,easy
%O A375909 1,3
%A A375909 _Paolo Xausa_, Sep 02 2024