A290016 Brazilian numbers which have exactly three Brazilian representations.

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

Offset: 1

Author

Bernard Schott, Jul 27 2017

Keywords

• nonn

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.

Examples

			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.
		

Crossrefs

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

Programs

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 *)