A383027 - OEIS

%I #12 May 11 2025 17:39:40

%S 3,7,17,83,167,583,1833,8167,10583,41833,191833,489417,1989417,

%T 9958167,25041833,74958167,125041833,831989417,1625041833,9874958167,

%U 15831989417,65831989417,309874958167,834168010583,1809874958167,6809874958167,29165831989417,51809874958167,179165831989417

%N a(n) is the number whose reversed n-digit square is the largest among all reversals of n-digit squares.

%e a(3)=17 because 982 (reverse of 17^2=289) is the largest reverse of all 3-digit squares.

%t a[n_]:=Module[{s=Ceiling[Sqrt[10^(n-1)]]},max=IntegerReverse[s^2];

%t For[k=s,k<=Floor[Sqrt[(10^n-1)]],k++,t=IntegerReverse[k^2];

%t If[t>max,max=t;s=k]];s];Table[a[n],{n,10}]

%Y Cf. A002942.

%K nonn,base,easy

%O 1,1

%A _Zhining Yang_, Apr 13 2025