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A239589 Numbers whose squares are cyclops numbers.

%I A239589 #13 Jun 25 2022 11:59:59
%S A239589 0,105,138,145,155,179,195,205,217,226,241,243,255,257,259,274,295,
%T A239589 305,1054,1068,1082,1091,1114,1127,1136,1158,1162,1175,1192,1196,1221,
%U A239589 1229,1233,1237,1261,1269,1273,1277,1281,1308,1323,1327,1338,1364,1375,1386
%N A239589 Numbers whose squares are cyclops numbers.
%H A239589 Colin Barker, <a href="/A239589/b239589.txt">Table of n, a(n) for n = 1..4000</a>
%e A239589 138 is in the sequence because 138^2 = 19044, which is a cyclops number.
%o A239589 (PARI)
%o A239589 is_cyclops(k) = {
%o A239589   if(k==0, return(1));
%o A239589   my(d=digits(k), j);
%o A239589   if(#d%2==0 || d[#d\2+1]!=0, return(0));
%o A239589   for(j=1, #d\2, if(d[j]==0, return(0)));
%o A239589   for(j=#d\2+2, #d, if(d[j]==0, return(0)));
%o A239589   return(1)}
%o A239589 s=[]; for(n=0, 2000, if(is_cyclops(n^2), s=concat(s, n))); s
%Y A239589 Cf. A000290, A134808, A160711, A239587, A239588, A239590, A239591.
%K A239589 nonn,base
%O A239589 1,2
%A A239589 _Colin Barker_, Mar 24 2014