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A267795 Integers n such that n, 2n, 3n ... 10n contain almost equally many copies of each base 10 digit. 1
1, 9, 109, 909, 10909, 90909, 1090909, 9090909, 13431958, 25834963, 32973507, 38296415, 45096237, 51546969, 94845303, 96237045, 109090909, 113431958, 126084879, 132868745, 132875488, 133595248, 134319558, 134755956, 134758658, 137584878, 143865844, 153584878 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Here 'almost equally many' means that the most common digit appears only once more than the least common.

LINKS

Lars Blomberg, Table of n, a(n) for n = 1..4000

EXAMPLE

The first 10 multiples of 109 are 109, 218, 327, 436, 545, 654, 763, 872, 981, 1090. Every digit appears 3 times except for '1' which appears 4 times. It is clear that all numbers of the form 10909..0909 and 90909..0909 appear in the list, and it seems likely that these are the only members.

PROG

(Python)

def f(n):

    """ This returns True iff n is in the sequence """

    l = [ n * i for i in range(1, 11) ]

  s = "".join(str(i) for i in l)

  c = [ s.count(str(j)) for j in range(10) ]

  return min(c) >= max(c) - 1

CROSSREFS

Cf. A038365.

Sequence in context: A157906 A166846 A058421 * A128876 A199030 A288692

Adjacent sequences:  A267792 A267793 A267794 * A267796 A267797 A267798

KEYWORD

nonn,easy,base

AUTHOR

Jack W Grahl, Jan 20 2016

EXTENSIONS

a(7)-a(28) from Lars Blomberg, Aug 11 2016

STATUS

approved

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Last modified June 22 17:18 EDT 2021. Contains 345388 sequences. (Running on oeis4.)