A036508 - OEIS

%I #14 Jul 14 2019 17:51:14

%S 1,121,11881,1110916,11431161,111112681,11112111396,171511111321,

%T 1113111511681,105111111121641,6111111111571216,111611104111115361,

%U 1411111111712116441,1113101111111117041,1111116080161111121161,11111119101145491111121,516116117111111111421121

%N Smallest square containing exactly n 1's.

%C a(17) > 4*10^23. - _Jon E. Schoenfield_, Jan 04 2009

%C a(20) > 10^28. - _Giovanni Resta_, Jul 27 2018

%H Giovanni Resta, <a href="/A036508/b036508.txt">Table of n, a(n) for n = 1..19</a>

%t a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 1] != n, k++]; k^2]; Array[a, 7] (* _Giovanni Resta_, Jul 27 2018 *)

%Y Cf. A048346.

%K nonn,base

%O 1,2

%A _David W. Wilson_

%E a(13)-a(16) from _Jon E. Schoenfield_, Jan 05 2009

%E a(17) from _Giovanni Resta_, Jul 27 2018