A239589 Numbers whose squares are cyclops numbers.

0, 105, 138, 145, 155, 179, 195, 205, 217, 226, 241, 243, 255, 257, 259, 274, 295, 305, 1054, 1068, 1082, 1091, 1114, 1127, 1136, 1158, 1162, 1175, 1192, 1196, 1221, 1229, 1233, 1237, 1261, 1269, 1273, 1277, 1281, 1308, 1323, 1327, 1338, 1364, 1375, 1386

Offset

1,2

Links

Colin Barker, Table of n, a(n) for n = 1..4000

Example

138 is in the sequence because 138^2 = 19044, which is a cyclops number.

Prog

(PARI)
is_cyclops(k) = {
  if(k==0, return(1));
  my(d=digits(k), j);
  if(#d%2==0 || d[#d\2+1]!=0, return(0));
  for(j=1, #d\2, if(d[j]==0, return(0)));
  for(j=#d\2+2, #d, if(d[j]==0, return(0)));
  return(1)}
s=[]; for(n=0, 2000, if(is_cyclops(n^2), s=concat(s, n))); s

Crossrefs

Cf. A000290, A134808, A160711, A239587, A239588, A239590, A239591.

Sequence in context: A097217 A115935 A069702 * A203614 A252069 A133509

Adjacent sequences: A239586 A239587 A239588 * A239590 A239591 A239592

Keyword

nonn,base

Author

Colin Barker, Mar 24 2014

Status

approved