A364405 - OEIS

%I #19 Aug 26 2023 02:52:53

%S 12,16,20,24,38,46,48,50,54,56,66,70,78,81,84,88,91,96,98,99,100,104,

%T 116,122,126,130,132,135,138,141,148,150,155,156,161,162,164,166,168,

%U 176,180,182,193,196,200,201,204,205,210,212,214,218,220,228,232,234,236

%N Numbers k such that k is never the smallest number which requires the maximum number of steps for the Euclidean algorithm for computing gcd(k,m) for any m > k.

%C Positive numbers not in A084242.

%o (Ruby)

%o def gcdsteps(k, m)

%o   k.zero? ? 0 : 1 + gcdsteps(m % k, k)

%o end

%o flags = [nil, *1..2000]

%o (1..flags.length).each do |m|

%o   scores = []

%o   (1..m).each do |k|

%o     scores << [gcdsteps(k, m), k]

%o   end

%o   flags[scores.sort_by { |n| -n[0] }.first[1]] = nil

%o end

%o puts flags[1..flags.length / 2].compact

%Y Cf. A084242, A051010.

%K nonn

%O 1,1

%A _John Metcalf_, Jul 22 2023