A027675 When squared gives number composed of digits {1,4,9}.

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

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 arithmetic-digits-squares-three.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