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Least k such that A352483(k) = 2*n-1, or -1 if no such k exists.
1

%I #8 Mar 30 2022 09:41:32

%S 3,5,7,20,11,13,32,17,19,44,23,27,216,29,31,35,280,37,117,41,43,92,47,

%T 51,153,53,57,116,59,61,65,520,67,207,71,73,77,616,79,164,83,87,261,

%U 89,93,95,760,97,105,101,103,212,107,109,333,113,920,119,952,123,125,1000,127,135,131

%N Least k such that A352483(k) = 2*n-1, or -1 if no such k exists.

%H Michel Marcus, <a href="/A352710/b352710.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A351913(2*n-1).

%o (PARI) f(n) = my(d=numdiv(n)); denominator(n*d/(n-d)); \\ A352483

%o a(n) = {my(k=3, q=2*n-1); while (f(k) != q, k++); k; }

%Y Cf. A352483.

%Y Bisection of A351913.

%K nonn

%O 1,1

%A _Michel Marcus_, Mar 30 2022