A370522 - OEIS

%I #43 Apr 04 2024 10:45:00

%S 7,83,836,8937,94863,987917,9893887,99477133,994927133,9380293167,

%T 99497231067,926174913167,9892825177313,89324067192437,

%U 943291047332683,9949874270443813,83066231922477313,707106074079263583,9429681807356492126,94180040294109027313,888142995231510436417,8882505274864168010583

%N a(n) is the least n-digit number whose square has the maximum sum of digits (A348300(n)).

%C a(n) is the last n-digit term in A067179.

%C As the last two of the only nine known numbers whose square has a digit mean above 8.25 (see A164841), there is a high probability that a(30)=314610537013606681884298837387 and a(31)=9984988582817657883693383344833.

%H Zhining Yang, <a href="/A370522/b370522.txt">Table of n, a(n) for n = 1..24</a> (terms 11..24 from Zhao Hui Du)

%e a(3) = 836 because among all 3-digit numbers, 836 is the smallest whose square 698896 has the maximum sum of digits, 46 = A348300(3).

%t A348300={13,31,46,63,81,97,112,130,148,162,180};

%t A370522[n_]:=Do[If[Total@IntegerDigits[k^2]==A348300[[n]],Return[k];],{k,10^(n-1),10^n-1}];

%t Table[A370522[n],{n,8}]

%o (Python)

%o def A370522(n):

%o     A348300=[0,13,31,46,63,81,97,112,130,148,162,180]

%o     for k in range(10**(n-1), 10**n):

%o         if sum(int(d) for d in str(k**2))==A348300[n]:

%o             return(k)

%o print([A370522(n) for n in range(1,9)])

%Y Cf. A004159, A067179, A348300, A348303.

%K nonn,base

%O 1,1

%A _Zhining Yang_, Feb 21 2024

%E a(11)-a(24) from _Zhao Hui Du_, Feb 23 2024