A328782 Integers k such that k and k^2 contain the same number > 0 of digits zero in their decimal expansion.

0, 104, 105, 203, 205, 302, 303, 305, 402, 403, 405, 504, 505, 506, 507, 508, 509, 601, 602, 603, 605, 609, 701, 702, 703, 705, 708, 709, 801, 802, 803, 805, 901, 902, 903, 905, 906, 1006, 1007, 1008, 1009, 1011, 1012, 1013, 1014, 1016, 1017, 1018, 1019, 1021

Offset

1,2

Links

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

Example

703 and 494209 = 703^2 both have one zero digit in their decimal expansion.

Maple

f:= n-> numboccur(0, convert(n, base, 10)):
q:= n-> ((x, y)-> x>0 and x=y)(f(n), f(n^2)):
select(q, [$0..1030])[];  # Alois P. Heinz, Oct 28 2019

Mathematica

Select[Range[0, 1100], DigitCount[#, 10, 0] == DigitCount[#^2, 10, 0] > 0 &] (* Giovanni Resta, Feb 27 2020 *)

Crossrefs

Equals A328781 \ A052040.

Cf. A104315, A134844, A328780, A328783.

Sequence in context: A054904 A117845 A286812 * A163554 A045208 A366552

Adjacent sequences: A328779 A328780 A328781 * A328783 A328784 A328785

Keyword

nonn,base

Author

Bernard Schott, Oct 28 2019

Extensions

More terms from Alois P. Heinz, Oct 28 2019

Status

approved