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A345390 Numbers such that their set of divisors contains every digit at least twice. 1
540, 720, 760, 810, 918, 1080, 1140, 1170, 1260, 1404, 1440, 1512, 1520, 1530, 1560, 1620, 1740, 1800, 1820, 1824, 1836, 1872, 1890, 1908, 1960, 2016, 2028, 2052, 2070, 2072, 2088, 2106, 2112, 2124, 2142, 2156, 2160, 2184, 2208, 2280, 2340, 2380, 2430, 2508, 2520 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Compare to A095050: Numbers such that all ten digits are needed to write all positive divisors in decimal representation.

LINKS

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

EXAMPLE

The divisors of 918 are 1, 2, 3, 6, 9, 17, 18, 27, 34, 51, 54, 102, 153, 306, 459, and 918. Every digit appears at least twice. Thus, 918 is in this sequence.

MAPLE

q:= n-> (p-> is(min(seq(coeff(p, x, j), j=0..9))>1))(add(x^i, i=

     map(d-> convert(d, base, 10)[], [numtheory[divisors](n)[]]))):

select(q, [$10..2600])[];  # Alois P. Heinz, Apr 21 2022

MATHEMATICA

Select[Range[3000], Length[Transpose[Tally[Flatten[IntegerDigits[Divisors[#]]]]][[2]]] == 10 && Min[Transpose[Tally[Flatten[IntegerDigits[Divisors[#]]]]][[2]]] > 1 &]

CROSSREFS

Cf. A095050.

Sequence in context: A184546 A252386 A289221 * A261290 A253463 A255105

Adjacent sequences:  A345387 A345388 A345389 * A345391 A345392 A345393

KEYWORD

nonn,base

AUTHOR

Tanya Khovanova, Jun 17 2021

STATUS

approved

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Last modified May 28 16:37 EDT 2022. Contains 354119 sequences. (Running on oeis4.)