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A328783 Numbers k such that k and k^2 contain at least one zero but not the same number of 0's. 4
10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 101, 102, 103, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 201, 202, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 301, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 401, 410, 420, 430, 440, 450, 460, 470 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
This sequence is one of the three sequences whose numbers k and k^2 don't contain the same number of 0, the two others are A104315 and A134844.
LINKS
EXAMPLE
201 and 40401 = 201^2 have both at least one zero but not the same number of 0 in their decimal expansion, hence, 201 is a term.
MAPLE
f:= n-> numboccur(0, convert(n, base, 10)):
q:= n-> ((x, y)-> x>0 and y>0 and x<>y)(f(n), f(n^2)):
select(q, [$0..500])[]; # Alois P. Heinz, Oct 28 2019
MATHEMATICA
Select[Range[0, 470], (x = DigitCount[#, 10, 0]) > 0 && (y = DigitCount[ #^2, 10, 0]) > 0 && x != y &] (* Giovanni Resta, Feb 27 2020 *)
CROSSREFS
Sequence in context: A098394 A057169 A330562 * A342855 A201014 A096092
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Oct 28 2019
EXTENSIONS
More terms from Alois P. Heinz, Oct 28 2019
STATUS
approved

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Last modified July 22 23:31 EDT 2024. Contains 374544 sequences. (Running on oeis4.)