A239828 Cyclops numbers which are squares of cyclops numbers.

0, 11025, 42025, 93025, 121308196, 121506529, 121903681, 122301481, 144408289, 144504441, 145106116, 145805625, 145902241, 169702729, 169806961, 171505216, 196308121, 196504324, 197205849, 197908624, 198105625, 198302724, 256608361, 256704484, 257409936

Offset

1,2

Comments

Subsequence of A160711.

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000

Formula

a(n) = A239827(n)^2.

Example

145106116 is in the sequence because 145106116 = 12046^2, and both 145106116 and 12046 are cyclops numbers.

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, 100000, if(is_cyclops(n) && is_cyclops(n^2), s=concat(s, n^2))); s

Crossrefs

Cf. A134808, A160711, A239827.

Sequence in context: A285845 A160711 A129087 * A156942 A325311 A164518

Adjacent sequences: A239825 A239826 A239827 * A239829 A239830 A239831

Keyword

nonn,base

Author

Colin Barker, Mar 27 2014

Status

approved