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A239827 Cyclops numbers whose squares are cyclops numbers. 3
0, 105, 205, 305, 11014, 11023, 11041, 11059, 12017, 12021, 12046, 12075, 12079, 13027, 13031, 13096, 14011, 14018, 14043, 14068, 14075, 14082, 16019, 16022, 16044, 16072, 16075, 17012, 17091, 17094, 18014, 18039, 18075, 18086, 19016, 19029, 19037, 19058 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Subsequence of A239589.

LINKS

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

FORMULA

a(n) = sqrt(A239828(n)).

EXAMPLE

12046 is in the sequence because 12046^2 = 145106116, and both 12406 and 145106116 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))); s

CROSSREFS

Cf. A134808, A239589, A239828.

Sequence in context: A347881 A044337 A044718 * A273521 A214082 A069692

Adjacent sequences:  A239824 A239825 A239826 * A239828 A239829 A239830

KEYWORD

nonn,base

AUTHOR

Colin Barker, Mar 27 2014

STATUS

approved

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Last modified July 2 10:39 EDT 2022. Contains 355004 sequences. (Running on oeis4.)