A318700 Positive numbers that contain odd and even digits.

10, 12, 14, 16, 18, 21, 23, 25, 27, 29, 30, 32, 34, 36, 38, 41, 43, 45, 47, 49, 50, 52, 54, 56, 58, 61, 63, 65, 67, 69, 70, 72, 74, 76, 78, 81, 83, 85, 87, 89, 90, 92, 94, 96, 98, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 112, 114, 116, 118, 120, 121, 122

Offset: 1

Author

Enrique Navarrete, Aug 31 2018

Keywords

• nonn
• base
• easy

Comments

The sequence of first differences takes on the values {1, 2, 3} only, and each of these values occurs infinitely often (the values 1 and 2 are clear; for the value 3, note that consecutive numbers such as 199..9, 200..0 and 399..9, 400..0 that are excluded from the sequence occur infinitely often).

Numbers n such that A065031(n) is a term of A111066. - Felix Fröhlich, Sep 01 2018

Nonnegative integers excluding those such that digits in their decimal representation share all the same parity. - R. J. Cano, Sep 10 2018

Examples

			49 and 50 are in the sequence but 19 and 20 are not.
		

Links

• R. J. Cano, PARI program

Crossrefs

Cf. A065031, A111066, A030141, A054684, A227870.

Programs

Mathematica

Select[Range@ 122, Union[Mod[IntegerDigits[#], 2]] == {0, 1} &] (* Michael De Vlieger, Sep 04 2018 *)

PARI

is(n) = my(d=digits(n), v=[]); if(n < 10, return(0)); for(k=1, #d, v=concat(v, [d[k]%2])); vecmin(v)!=vecmax(v) \\ Felix Fröhlich, Sep 01 2018

PARI

See Cano link.