A030487 When squared gives number composed of digits {2, 5, 7}.

5, 15, 85, 165, 235, 1665, 15085, 16665, 166665, 268835, 1666665, 5076665, 16666665, 52683515, 165898335, 166666665, 278433515, 507668915, 850032485, 1508559835, 1666666665, 15085017485, 16666666665, 166666666665

Offset

1,1

Links

Zhao Hui Du, Table of n, a(n) for n = 1..45

Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences

Author?, Source(txt)

Example

5^2 = 25, so 5 is in the sequence.
15^2 = 225, so 15 is in the sequence.
25^2 = 625, which has a 2 and 5 but also a 6, so 25 is not in the sequence.

Mathematica

Select[5Range[1, 9999, 2], Complement[IntegerDigits[#^2], {2, 5, 7}] == {} &] (* Alonso del Arte, Feb 25 2020 *)

Crossrefs

Cf. A030485.

Sequence in context: A088935 A183937 A275971 * A165470 A165625 A058820

Adjacent sequences: A030484 A030485 A030486 * A030488 A030489 A030490

Keyword

nonn,base

Author

Patrick De Geest

Extensions

Extended and corrected by author 03/2000.

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 03 2005

Status

approved