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A323275 Let f(p, q) denote the pair (p + q, wt(p) + wt(q)); a(n) is obtained by iterating f starting at (n, 1) until p/q is an integer (and then a(n) is that integer), or if no integer is ever reached then a(n) = -1. (Here wt is binary weight, A000120.) 3

%I #38 Feb 02 2019 19:58:17

%S 1,2,2,2,2,2,2,10,7,10,3,7,5,10,7,22,6,22,5,7,8,22,10,10,8,8,10,10,6,

%T 8,22,8,22,8,9,8,10,8,8,22,10,22,22,22,22,22,8,15,22,11,15,15,22,11,

%U 16,16,22,15,10,16,15,22,15,14,22,14,17,23,40,15,22,22,40,12,22,22,16,12,18,27,18,40,40,40,22,40,14,18,34

%N Let f(p, q) denote the pair (p + q, wt(p) + wt(q)); a(n) is obtained by iterating f starting at (n, 1) until p/q is an integer (and then a(n) is that integer), or if no integer is ever reached then a(n) = -1. (Here wt is binary weight, A000120.)

%H Jeffrey C. Lagarias, <a href="https://arxiv.org/abs/math/0411141">Wild and Wooley Numbers</a>, arXiv preprint arXiv:math/0411141 [math.NT], 2004-2005.

%e (8, 1) -> (9, 2) -> (11, 3) -> (14, 5) -> (19, 5) -> (24, 5) -> (29, 4) -> (33, 5) -> (38, 4) -> (42, 4) -> (46, 4) -> (50, 5). 50/5 is an integer, so a(8) = 50/5 = 10.

%o (PARI) f(v) = return([v[1]+v[2], hammingweight(v[1])+hammingweight(v[2])]);

%o a(n) = {my(nb = 0, v = [n, 1]); while (1, v = f(v); nb++; if (frac(q=v[1]/v[2]) == 0, return (q)));} \\ _Michel Marcus_, Jan 13 2019

%Y Cf. A000120, A059175, A323375.

%K nonn,base

%O 1,2

%A _Ctibor O. Zizka_, Jan 12 2019

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Last modified April 25 07:41 EDT 2024. Contains 371964 sequences. (Running on oeis4.)