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A284758 The least positive integer that has exactly n different representations as Brazilian number. 5
1, 7, 15, 24, 40, 60, 144, 120, 180, 336, 420, 360, 900, 960, 720, 840, 1260, 1440, 2340, 1680, 2880, 3600, 8190, 2520, 9072, 9900, 6300, 6720, 20592, 5040, 10920, 7560, 31320, 98040, 25920, 10080, 21420, 177156, 74256, 15120, 28560, 20160 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The representation n = 11_(n-1) is not accepted under the definition of a Brazilian number.

REFERENCES

D. Lignon, Dictionnaire de (presque) tous les nombres entiers, Ellipses, 2012, page 420.

LINKS

Giovanni Resta, Table of n, a(n) for n = 0..100

EXAMPLE

a(0) = 1 because 1 is the smallest non-Brazilian number.

a(4) = 40 because 40 = 1111_3 = 55_7 = 44_9 = 22_19 and 40 is the smallest integer with four Brazilian representations.

MATHEMATICA

rep[n_] := Length@ Select[Range[2, n/2], 1 == Length@ Union@ IntegerDigits[n, #] &]; a[n_] := Block[{k=1}, While[rep[k] != n, k++]; k]; a /@ Range[0, 15] (* Giovanni Resta, Apr 04 2017 *)

CROSSREFS

Cf. A066044, A066460, A125134.

Sequence in context: A184920 A076796 A056119 * A211430 A082111 A323483

Adjacent sequences:  A284755 A284756 A284757 * A284759 A284760 A284761

KEYWORD

nonn,base

AUTHOR

Bernard Schott, Apr 04 2017

STATUS

approved

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Last modified February 23 08:36 EST 2019. Contains 320420 sequences. (Running on oeis4.)