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A239828 Cyclops numbers which are squares of cyclops numbers. 4
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 28 08:06 EST 2020. Contains 332321 sequences. (Running on oeis4.)