

A027675


When squared gives number composed of digits {1,4,9}.


4



1, 2, 3, 7, 12, 21, 38, 107, 212, 31488, 70107, 387288, 95610729, 446653271, 3148717107, 21081079479, 648070211589107021
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OFFSET

1,2


COMMENTS

If a number has a least significant digit of 0, 4, 5 or 6, it can't be in this sequence.  Alonso del Arte, Jun 11 2016


LINKS

Table of n, a(n) for n=1..17.
Chris, Three Digits Solution, June 29, 2005.
Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences
Patrick De Geest, Palindromic Squares
A. Ottens, The arithmeticdigitssquaresthree.digits problem [broken link].
Eric Weisstein's World of Mathematics, Square Number.


EXAMPLE

Since 107^2 = 11449, 107 is in the sequence.
As 108^2 = 11664 has two 6's, 108 is not in the sequence.


MATHEMATICA

Select[Range[100], Complement[IntegerDigits[#^2], {1, 4, 9}] == {} &] (* Alonso del Arte, Jun 11 2016 *)


CROSSREFS

Cf. A006716.
Sequence in context: A222196 A184696 A298341 * A298353 A054176 A289977
Adjacent sequences: A027672 A027673 A027674 * A027676 A027677 A027678


KEYWORD

nonn,base,more


AUTHOR

Patrick De Geest


STATUS

approved



