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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 Giovanni Resta, Table of n, a(n) for n = 1..10000 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 Cf. A052040, A104315, A134844, A328780, A328781, A328782. Sequence in context: A098394 A057169 A330562 * A342855 A201014 A096092 Adjacent sequences: A328780 A328781 A328782 * A328784 A328785 A328786 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.)