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A197722 Smallest number k such that k^2 begins with n^3. 0


%S 1,9,52,8,112,147,586,716,27,100,1154,4157,4688,5239,581,64,22166,

%T 2415,2619,28285,30432,10319,34882,37181,125,41924,44366,46853,15617,

%U 51962,54582,18102,59948,62693,207063,216,71171,74076,77019,800,83019,272192,28197

%N Smallest number k such that k^2 begins with n^3.

%e a(6) = 147 because 147^2 = 21609 starts with 216 = 6^3.

%t f[n_]:=Block[{k = 0, m}, While[m = Max[0, Floor@Log[10, k^2]-Floor@Log[10, n^3]]; (k^2-Mod[k^2, 10^m])/10^m != n^3, k++]; k]; Array[f, 43]

%Y See A138173 (smallest m such that m^3 begins with n^2).

%K nonn,base

%O 1,2

%A _Michel Lagneau_, Oct 17 2011

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Last modified December 3 05:05 EST 2021. Contains 349445 sequences. (Running on oeis4.)