A030691 - OEIS

%I #16 Oct 30 2018 10:31:01

%S 5,16,21,55,63,154,17,40,201,10,23,113,257,27,609,295,307,148,1535,

%T 342,164,1692,809,1793,397,878,90,428,944,4482,987,1008,1029,4872,107,

%U 2349,5154,5247,2478,252,552,5609,5697,5785,2726,1284,2806,6131

%N Cube root of A030690.

%C Smallest m such that m^3 begins with n^2.

%H Zak Seidov, <a href="/A030691/b030691.txt">Table of n, a(n) for n = 1..1000</a>

%e a(4)=55 because 55^3=166375 begins with 4^2=16. - _Zak Seidov_, Oct 18 2011

%t s={}; Do[If[n==3, AppendTo[s,21], k=1; While[(ra=Range[Ceiling[(n^2*10^k)^(1/3)], Floor[((n^2+1)*10^k)^(1/3)]]) == {}, k++]; AppendTo[s, ra[[1]]]], {n,100}]; s (* _Zak Seidov_, Oct 18 2011 *)

%K nonn,base

%O 1,1

%A _Patrick De Geest_