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A290016 Brazilian numbers which have exactly three Brazilian representations. 4
24, 36, 42, 54, 66, 70, 78, 88, 100, 102, 104, 105, 124, 128, 130, 135, 136, 138, 152, 154, 165, 171, 172, 174, 182, 184, 186, 189, 190, 195, 196, 225, 230, 231, 232, 238, 242, 246, 248, 250, 256, 258, 272, 282, 286, 290, 292, 296, 297, 310, 318, 322, 328, 333, 344, 345 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

These numbers could be called 3-Brazilian numbers.

All these numbers are composite with six to ten different divisors.

The smallest number of this sequence is 24 with 24 = 44_5 = 33_7 = 22_11. The number 24 is highly Brazilian in A329383.

LINKS

Table of n, a(n) for n=1..56.

EXAMPLE

36 = 4 * 9 = 44_8 = 3 * 12 = 33_11 = 2 * 18 = 22_19.

42 = 2 * 21 = 22_20 = 222_4 = 3 * 14 = 33_13.

124 = 4 * 31 = 44_30 = 444_5 = 2 * 62 = 22_61.

272 = 8 * 34 = 88_33 = 4 * 68 = 44_67 = 2 * 136 = 22_135.

MATHEMATICA

Flatten@ Position[#, 3] &@ Table[Count[Range[2, n - 2], _?(And[Length@ # != 1, Length@ Union@ # == 1] &@ IntegerDigits[n, #] &)], {n, 350}] (* Michael De Vlieger, Jul 30 2017 *)

CROSSREFS

Cf. A125134, A220570, A220571, A257521, A288783, A290015, A290017, A290018, A329383.

Sequence in context: A307342 A067341 A307682 * A330880 A195008 A054775

Adjacent sequences:  A290013 A290014 A290015 * A290017 A290018 A290019

KEYWORD

nonn

AUTHOR

Bernard Schott, Jul 27 2017

STATUS

approved

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Last modified September 18 04:44 EDT 2020. Contains 337165 sequences. (Running on oeis4.)